JP2015055317A - Ball seat and ball valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball seat capable of being replaced into fluororesin ball seat and having excellent molding processability, and a ball valve using the ball seat.SOLUTION: A ball seat 10A is an endless ball seat 30A that seals a ball 4 having a through hole 4B by contacting with an external surface 4A of the ball 4 in a ball valve rotatably mounted into bodies 1, 2. In the ball seat 30A, a carbon nano-tube with the average diameter of 2-100 nm, and tetrafluoroethylene perfluoroalkyl vinyl ether-based fluororesin (PFA) are contained in the matrix of perfluoro-elastomer (FFKM).

Description

  The present invention relates to a ball seat using carbon nanotubes and a ball valve using the ball seat.

  Conventionally, ball valves have a low fluid resistance, a spherical shape and a compact shape, and a relatively simple structure with few parts and easy maintenance. From the water and sewage systems of households to the power industry and natural gas pipelines. Widely used (see, for example, Non-Patent Document 1).

  In the floating type ball valve and the trunnion type ball valve, a ball that is rotatably disposed on a flow path formed in the body, a through hole communicating with the flow path is formed, and the flow path is opened and closed by the through hole; A ball seat provided on at least the inflow side or the outflow side of the fluid in the ball and in contact with the outer peripheral surface of the ball. The ball is made of metal that is precisely processed to a high sphericity. The ball sheet is formed in an annular shape, and is in contact with the outer peripheral surface of the ball to seal between the flow path and the cavity in the body.

  As the material for the ball sheet, PCTFF, PTFE, modified PTFE (PFA + PTFE), filled PTFE, PFA, polyether-based, nylon-based or the like resin is used (for example, see Patent Document 1).

  In particular, depending on the use environment of the ball valve, there is a piping application that can be handled only by a fluororesin ball sheet having excellent heat resistance and chemical resistance. For example, piping use in a chemical plant.

  In addition to the expensive material itself, the fluororesin ball sheet has many restrictions in molding processing, and a reduction in processing cost is required. A limitation in the molding process is that a fluororesin ball sheet cannot be mass-produced such as injection molding and must be heat-compressed. For example, PTFE is known to have to be sintered after preforming the powder, but even PFA that is capable of general melt molding, such as injection molding, at the grain boundaries of PFA particles In order to eliminate voids and cracks, powder compression molding is performed in a mold heated to the melting temperature. Such heat compression molding of fluororesin has a problem that the production efficiency does not increase because it is cooled slowly while being compressed in the mold. In addition, a ball sheet made of fluororesin is difficult to produce in accordance with the number of orders received from customers because a plurality of rings are cut out from a long cylindrical primary molded product and further cut. It was. Further, when the fluororesin is molded at a temperature higher than the melting temperature, gas is generated by thermal decomposition. Since the mold is corroded by the gas, there is a problem that the mold is rapidly deteriorated.

  In addition, in order to improve the mechanical characteristics of the fluororesin molded product, it has been proposed to add various fillers. For example, a resin composition in which fluorine-containing elastomer particles and an inorganic filler such as a nano filler are blended with a fluororesin has been proposed (for example, see Patent Document 2). According to this resin composition, the material permeation blocking properties, mechanical properties, heat resistance, flame retardancy, conductivity, etc. of the fluororesin are improved. However, the moldability of the fluororesin has not been improved yet.

On the other hand, carbon fiber composite materials and seal members in which carbon nanotubes are blended with fluorine-containing elastomers have been proposed (see, for example, Patent Document 3 and Patent Document 4). In addition, a seal member in which carbon nanotubes are blended with perfluoroelastomer (FFKM) has been proposed (for example, Patent Document 5). Such a fluorine-containing elastomer composite material can improve a high volume resistivity and perfluoropolyether resistance, but its application as a substitute for a fluororesin product is not considered.

JP 2007-23320 A JP 2009-52028 A JP 2013-83340 A International Publication No. 2011-77598 JP 2013-23575 A

“Ball Valve General Catalog” published on the homepage of KITZ, Inc. [searched on August 18, 2012], Internet <http: // www. kitz. co. jp / product / pdf / ben / J-201-50. pdf>

  The present invention provides a ball sheet excellent in moldability that can be replaced with a fluororesin ball sheet, and a ball valve using the ball sheet.

The ball seat according to the present invention is
An endless ball seat that contacts and seals with the outer surface of a ball valve in which a ball having a through hole is rotatably mounted in the body,
The perfluoroelastomer (FFKM) matrix contains carbon nanotubes having an average diameter of 2 nm to 100 nm and tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA).

  According to the ball sheet of the present invention, since the ball sheet can be manufactured by a perfluoroelastomer (FFKM) molding method, it can be manufactured without melting the fluororesin, and the productivity of the ball sheet is improved. . Further, according to the ball sheet of the present invention, the grain boundaries of tetrafluoroethylene / perfluoroalkyl vinyl ether-based fluororesin (PFA) are made dense with perfluoroelastomer (FFKM) reinforced with carbon nanotubes. The sealing performance of the seat is improved and the increase in the opening / closing torque of the ball valve is suppressed by including a tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA).

In the ball seat according to the present invention,
Tetrafluoroethylene perfluoroalkyl vinyl ether fluororesin (PFA) can be 5 to 150 parts by mass with respect to 100 parts by mass of perfluoroelastomer (FFKM).

  Since the ball seat according to the present invention can be cut, it can be applied to a ball valve that requires high dimensional accuracy. Moreover, according to the ball sheet concerning this invention, since it can manufacture by the kneading | mixing process of an elastomer, it is excellent in productivity.

In the ball seat according to the present invention,
The compounding amount of the carbon nanotube is 0.5 to 50 parts by mass with respect to 100 parts by mass of the perfluoroelastomer (FFKM). Tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA) and perfluoroelastomer It can be 0.2 to 47.6 parts by mass with respect to 100 parts by mass of the matrix combined with (FFKM).

  The ball seat according to the present invention can maintain low torque when the ball valve is opened and closed while being excellent in sealing performance.

In the ball seat according to the present invention,
The carbon nanotube is a multi-walled carbon nanotube having an average diameter of 9 nm to 20 nm,
The multi-walled carbon nanotube contains 0.5 to 50 parts by mass with respect to 100 parts by mass of perfluoroelastomer (FFKM),
The tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA) can contain a swelling inhibitor composed of a sulfur-containing compound and an amine compound.

  The ball sheet according to the present invention can be excellent in monomer resistance. In particular, according to the ball sheet of the present invention, there is little swelling due to butadiene gas.

The ball valve according to the present invention is
It is a ball valve using the ball seat.

  According to the ball valve according to the present invention, it is possible to increase the price competitiveness of the ball valve by improving the productivity of the ball seat and reducing the processing cost. Further, according to the ball valve of the present invention, an increase in the opening / closing torque of the ball valve can be suppressed while the sealing performance is improved.

It is a mimetic diagram for explaining the 1st kneading process of the manufacturing method of the ball sheet concerning one embodiment of the present invention. It is a mimetic diagram for explaining the 1st kneading process of the manufacturing method of the ball sheet concerning one embodiment of the present invention. It is a mimetic diagram for explaining the 1st kneading process of the manufacturing method of the ball sheet concerning one embodiment of the present invention. It is a schematic diagram for demonstrating the 2nd kneading | mixing process of the manufacturing method of the ball sheet which concerns on one Embodiment of this invention. It is a schematic diagram for demonstrating the formation process of the manufacturing method of the ball sheet which concerns on one Embodiment of this invention. It is a schematic diagram for demonstrating the formation process of the manufacturing method of the ball sheet which concerns on one Embodiment of this invention. It is a perspective view of the ball seat concerning one embodiment of the present invention. It is a longitudinal section of a ball valve concerning one embodiment of the present invention. It is a longitudinal section of a ball valve concerning one embodiment of the present invention. It is a perspective view showing the longitudinal section of the ball valve concerning one embodiment of the present invention. It is a schematic block diagram of the evaluation apparatus which evaluates the monomer resistance of the ball sheet which concerns on one Embodiment of this invention. It is a schematic block diagram of the evaluation apparatus which evaluates the monomer resistance of the ball valve which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  A ball seat according to an embodiment of the present invention is an endless ball seat that contacts and seals the outer surface of a ball valve in which a ball having a through hole is rotatably mounted in the body, The perfluoroelastomer (FFKM) matrix contains carbon nanotubes having an average diameter of 2 nm to 100 nm and tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA).

  It is a ball valve using the ball seat concerning one embodiment of the present invention.

(I) Perfluoroelastomer (FFKM)
In the perfluoroelastomer (FFKM) used in the present embodiment, the hydrogen atom (H) bonded to the carbon atom constituting the main chain carbon (C) -carbon (C) bond is completely fluorinated. Fluoro rubber. Examples of the perfluoroelastomer include tetrafluoroethylene (TFE) / perfluoroalkyl vinyl ether (PAVE) copolymer, and examples of the perfluoroalkyl vinyl ether (PAVE) that can be used here include , Perfluoromethoxyvinyl ether (PMOVE), perfluoromethyl vinyl ether (PMVE), perfluoroethyl vinyl ether (PEVE), perfluoropropyl vinyl ether (PPVE) and other similar compounds.

  In general, perfluoroelastomer (FFKM) is excellent in heat resistance and chemical resistance, but is inferior in low temperature characteristics. For example, TR-10 value in a low temperature elastic recovery test (TR test) according to JIS K6261 Although it is usually around 0 ° C., as a perfluoroelastomer (FFKM), it has excellent low temperature characteristics, has a TR-10 value of −10 ° C. or less in a low temperature elastic recovery test (TR test) according to JIS K6261, and TR- The 10 value can be −15 ° C. or less, and in particular, the TR-10 value can be −20 ° C. or less.

  Examples of the perfluoroelastomer (FFKM) include Du Pont's trade name Kalrez (registered trademark), Solvay's trade name Technoflon (registered trademark), Daikin Industries, Ltd. trade name Perflo (registered trademark), and the like. I can give you.

  For the perfluoroelastomer (FFKM), a known crosslinking agent can be used, and for example, polyamine vulcanization, polyol vulcanization, or peroxide vulcanization can be performed. By cross-linking perfluoroelastomer (FFKM) with a cross-linking agent, a ball sheet excellent in heat resistance and chemical resistance can be produced.

  Also, for perfluoroelastomer (FFKM), reinforcing agents such as white carbon used as a general compounding agent for rubber, fillers such as talc, clay, graphite, calcium silicate, stearic acid, palmitic acid Further, processing aids such as paraffin wax, anti-aging agents, plasticizers, and the like can be appropriately added and used as necessary.

Perfluoroelastomer (FFKM) has a halogen group having an affinity for a carbon nanotube, particularly a radical at its end. Carbon nanotubes usually have a six-membered ring of carbon atoms and a closed end with a five-membered ring introduced at the tip, but they are structurally unreasonable and cause defects in practice. It is easy to generate radicals and functional groups in the part. Further, at least one of the main chain, side chain and terminal chain of perfluoroelastomer (FFKM) has a halogen group having high affinity (reactivity or polarity) with the radical of carbon nanotube, so that perfluoroelastomer (FFKM) Can be bonded to the carbon nanotube. This makes it easier to disperse the carbon nanotubes than the cohesive force.

  Perfluoroelastomer (FFKM) can be kneaded with carbon nanotubes in an uncrosslinked form.

(II) Carbon nanotube The carbon nanotube used in the present embodiment has an average diameter of more than 2 nm and not more than 100 nm. Furthermore, the carbon nanotubes can have an average diameter of more than 9 nm and not more than 100 nm, in particular, the average diameter can be more than 9 nm and not more than 20 nm. Carbon nanotubes having an average diameter of 9 nm or less can obtain excellent normal physical properties by disaggregating aggregates and evenly dispersing them throughout the ball sheet even in a small amount, but are generally expensive. Moreover, the average diameter of carbon nanotubes generally available as 10 nm class carbon nanotubes is more than 9 nm and not more than 20 nm, and is excellent in improving the tensile strength (TS) in the normal physical properties of the ball sheet. Carbon nanotubes having an average diameter of more than 20 nm and not more than 100 nm are excellent in price competitiveness, excellent in elongation at break (Eb) in normal properties of the ball sheet, and can have high flexibility. The average diameter and average length of the carbon nanotubes are measured by measuring diameters and average lengths of 200 or more locations from, for example, 5,000 times imaging with a scanning electron microscope (the magnification can be changed as appropriate depending on the size of the carbon nanotubes). It can be obtained by calculating as an arithmetic average value.

  The compounding amount of the carbon nanotube in the ball sheet is 0.5 to 50 parts by mass with respect to 100 parts by mass of the perfluoroelastomer (FFKM), and includes tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA) and It can be 0.2 mass part-47.6 mass parts with respect to 100 mass parts of matrices which combined the perfluoroelastomer (FFKM). Furthermore, the ball sheet can contain 0.5 to 50 parts by mass of carbon nanotubes, and particularly 2 to 40 parts by mass of carbon nanotubes with respect to 100 parts by mass of perfluoroelastomer (FFKM). Can do. Carbon nanotubes tend to aggregate and are generally dispersed in a matrix in the form of aggregates, but the carbon nanotubes in the first phase of the ball sheet are not aggregates but in a perfluoroelastomer (FFKM) matrix in a fibrillated state. Exist in a distributed manner. The compounding quantity of a carbon nanotube can be adjusted with the compounding quantity of a fluororesin particle according to the use of a ball sheet. Heat resistance and chemical resistance can be improved if the carbon nanotubes are 0.5 parts by mass or more, and if the carbon nanotubes are 50 parts by mass or less with respect to 100 parts by mass of perfluoroelastomer (FFKM), flexibility and Compression characteristics can be improved.

  The carbon nanotube has a single-layer structure or a multi-layer structure in which one surface (graphene sheet) of graphite having a carbon hexagonal mesh surface is wound into a cylindrical shape, and a multi-layer structure has a multi-layer carbon nanotube (MWNT: multi-wall structure). Wall carbon nanotube), vapor-grown carbon fiber, and the like.

Such carbon nanotubes can be produced by various vapor phase growth methods. The vapor phase growth method is a method in which hydrocarbons such as benzene and toluene are thermally decomposed in the gas phase to synthesize carbon nanotubes. More specifically, a fluid catalyst method, a zeolite supported catalyst method, and the like can be exemplified. The carbon nanotubes can be obtained, for example, by subjecting an organic compound such as benzene, toluene or natural gas as a raw material to a thermal decomposition reaction at 800 ° C. to 1300 ° C. with hydrogen gas in the presence of a transition metal catalyst such as ferrocene. The carbon nanotubes can be graphitized at 2300 ° C. to 3200 ° C., for example, together with a graphitization catalyst such as boron, boron carbide, beryllium, aluminum, and silicon.

  The carbon nanotubes can be improved in adhesion and wettability with the elastomer by performing a surface treatment such as ion implantation treatment, sputter etching treatment, or plasma treatment in advance before being kneaded with the elastomer.

(III) Fluororesin The tetrafluoroethylene / perfluoroalkyl vinyl ether-based fluororesin (PFA) can be in the form of particles, and the average particle diameter thereof can be 10 nm to 500 μm. If the average particle size of the fluororesin is 500 μm or less, processing in the kneading step is possible, and if it is 10 nm or more, it is commercially available.

  Tetrafluoroethylene perfluoroalkyl vinyl ether fluororesin (PFA) can be 5 to 150 parts by mass with respect to 100 parts by mass of perfluoroelastomer (FFKM). Cutting work is possible because tetrafluoroethylene perfluoroalkyl vinyl ether fluororesin (PFA) is 5 parts by mass or more per 100 parts by mass of perfluoroelastomer (FFKM), and 150 parts by mass or less. And kneading with carbon nanotubes.

  The tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA) can contain a swelling inhibitor. Examples of the low molecular weight organic compound that can swell the fluororesin include polymerizable monomers and reactive (polymerizable) oligomers in the polymerization reaction. In particular, the ball valve may be used for piping of a polymerization reactor such as synthetic rubber or synthetic resin, and the polymerizable monomer or reactive oligomer introduced into the polymerization reactor may swell the fluororesin ball sheet. As a result, a change in the opening / closing torque, the occurrence of fine cracks in the ball sheet, and the influence on the sealing performance due to wear of the ball sheet are problematic.

  Examples of the polymerizable monomer include diene monomers such as butadiene and chloroprene; styrene monomers such as styrene and α-methylstyrene; halogenated ethylenically unsaturated monomers such as vinyl chloride and vinylidene chloride: acrylonitrile monomers such as acrylonitrile; Acrylic acid monomers such as acrylic acid and acrylate esters: Methacrylic acid monomers such as methacrylic acid and methacrylate esters; Unsaturated carboxylic acid monomers such as maleic acid; Olefin monomers: Vinyl ester monomers; Vinyl ether monomers; Acetylene monomers; vinyl ketone monomers; vinyl amide monomers; maleimide monomers; acrylamide monomers; ring-opening polymerizable monomers; phenol derivative monomers It is.

(IV) Ball Sheet A ball sheet is an endless ball sheet that is brought into contact with the outer surface of a ball valve in which a ball having a through-hole is rotatably mounted in the body and sealed, and a perfluoroelastomer ( The FFKM) matrix contains carbon nanotubes having an average diameter of 2 nm to 100 nm and tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA).

  Further, the ball sheet has a first phase that is a continuous phase containing perfluoroelastomer (FFKM) and carbon nanotubes, and a second phase made of tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA). be able to. Carbon nanotubes can be defibrated and present in perfluoroelastomer (FFKM). The first phase can be formed to cover the second phase that is the dispersed phase.

  The ball sheet is an endless molded product having a through hole in the center as shown in FIGS.

  The first phase exists in a perfluoroelastomer (FFKM) matrix so that the carbon nanotubes are defibrated so that each carbon nanotube can be unwound one by one, and does not have an aggregate of carbon nanotubes. This can be confirmed by observing the frozen section of the ball sheet with a scanning electron microscope. If the carbon nanotubes are not defibrated, an aggregate of carbon nanotubes is confirmed as a black mass of about 1 μm to 50 μm by observation with a scanning electron microscope. However, in the first phase according to the present embodiment, an aggregate of carbon nanotubes cannot be observed by observation with a scanning electron microscope. Therefore, the first phase appears such that a part of the carbon nanotubes defibrated by observation with a scanning electron microscope is evenly scattered throughout the perfluoroelastomer (FFKM).

  The second phase is formed of tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA), and the PFA particles used for processing are greatly deformed by molding, but the first phase matrix is observed by observation with a scanning electron microscope. It can be confirmed that the islands are scattered in a sea-island shape.

  By having the second phase covered with the first phase, the ball sheet has a small coefficient of friction and excellent heat resistance. Further, the ball sheet can reduce the residual strain by having the second phase covered by the first phase. Furthermore, since the ball sheet has the second phase covered with the first phase, the swelling due to the polymerizable monomer or the like can be suppressed.

  The ball sheet is, for example, a multi-walled carbon nanotube having an average diameter of 9 nm to 20 nm, and the multi-walled carbon nanotube includes 0.5 to 50 parts by mass with respect to 100 parts by mass of perfluoroelastomer (FFKM). The ethylene / perfluoroalkyl vinyl ether fluororesin (PFA) can contain a swelling inhibitor comprising a sulfur-containing compound and an amine compound.

(V) Ball Sheet Manufacturing Method In this embodiment, an example using FIGS. 1 to 7 will be described as a ball sheet manufacturing method. The ball sheet manufacturing method includes a first kneading step in which perfluoroelastomer (FFKM) and carbon nanotubes are kneaded to obtain a first mixture, and tetrafluoroethylene / perfluoroalkyl vinyl ether-based fluororesin particles (hereinafter referred to as the first mixture). , PFA particles) and kneading to obtain a ball sheet.

  1-4 is a figure which shows typically the open roll method using the open roll 2 of two rolls. 1-4, the code | symbol 10 shows a 1st roll and the code | symbol 20 shows a 2nd roll. The first roll 10 and the second roll 20 are arranged at a predetermined interval d. The 1st and 2nd rolls 10 and 20 rotate by normal rotation or reverse rotation. In the illustrated example, the first roll 10 and the second roll 20 rotate in the direction indicated by the arrow.

  First, a 1st kneading process is demonstrated using FIGS. 1-3.

  As shown in FIG. 1, in a state where the first and second rolls 10 and 20 are rotated, perfluoroelastomer (FFKM) 30 is wound around the first roll 10 and mastication is performed. The distance d between the first roll 10 and the second roll 20 is set to 1.5 mm, for example.

  As shown in FIG. 2, a so-called bank 34 in which perfluoroelastomer (FFKM) 30 is accumulated is formed between the rolls 10 and 20. When the carbon nanotubes 80 are added to the bank 34 and the first and second rolls 10 and 20 are rotated, a mixture of the perfluoroelastomer (FFKM) 30 and the carbon nanotubes 80 is obtained. This mixture is removed from the open roll 2.

  As shown in FIG. 3, the distance d between the first roll 10 and the second roll 20 was further set to, for example, 0.5 mm or less, more preferably 0.1 mm to 0.5 mm. The mixture 36 is put into the open roll 2 and thinning is performed as a first thinning step. For example, the thinning can be performed about 3 to 10 times. When the surface speed of the first roll 10 is V1, and the surface speed of the second roll 20 is V2, the ratio of the surface speeds (V1 / V2) in thinness is 1.05 to 3.00. And can be 1.05 to 1.2. By using such a surface velocity ratio, a desired shear force can be obtained.

  The shearing force thus obtained causes a high shearing force to act on the perfluoroelastomer (FFKM) 30 so that the aggregated carbon nanotubes 80 are pulled out one by one into the perfluoroelastomer (FFKM) molecule. The first mixture 50 in which the carbon nanotubes 80 are dispersed in the perfluoroelastomer (FFKM) 30 is obtained.

  In this process, in order to obtain as high a shearing force as possible, the perfluoroelastomer (FFKM) and the carbon nanotubes can be mixed at 0 ° C. to 50 ° C., and further at a relatively low temperature of 5 ° C. to 30 ° C. Can be done. Such thinness at low temperature allows the carbon nanotubes to be efficiently defibrated and dispersed in the matrix because perfluoroelastomer (FFKM) has rubber elasticity.

  At this time, the perfluoroelastomer (FFKM) of the present embodiment has the above-described characteristics, that is, the elasticity, viscosity, and carbon nanotubes expressed by the molecular form (molecular length) and molecular motion of the perfluoroelastomer (FFKM). Can easily disperse carbon nanotubes by having a chemical interaction with them, so that it is possible to obtain a ball sheet matrix material with excellent dispersibility and dispersion stability (that carbon nanotubes are difficult to re-aggregate) it can. More specifically, when perfluoroelastomer (FFKM) and carbon nanotubes are mixed, viscous perfluoroelastomer (FFKM) penetrates into each other of carbon nanotubes, and a specific part of perfluoroelastomer (FFKM) Bind to the highly active part of the carbon nanotubes by chemical interaction. In this state, if a strong shearing force acts on a mixture of perfluoroelastomer (FFKM) having a relatively long molecular length and high molecular mobility (elasticity) and carbon nanotube, the movement of perfluoroelastomer (FFKM) is affected. At the same time, the carbon nanotubes move, and the aggregated carbon nanotubes are separated and defibrated by the restoring force of the perfluoroelastomer (FFKM) due to elasticity after shearing and dispersed in the perfluoroelastomer (FFKM). It will be.

  As shown in FIG. 3, when the mixture 36 is pushed out between narrow rolls by thinning, the first mixture 50 is deformed thicker than the roll interval d by the restoring force due to the elasticity of perfluoroelastomer (FFKM). It can be inferred that the deformation causes the mixture subjected to a strong shear force to flow more complicatedly and disperse the carbon nanotubes in the perfluoroelastomer (FFKM) while defibrating. The carbon nanotubes once dispersed are prevented from reaggregating due to chemical interaction with perfluoroelastomer (FFKM), and can have good dispersion stability.

  The step of dispersing carbon nanotubes in perfluoroelastomer (FFKM) by a shearing force is not limited to the open roll method, and a closed kneading method or a multiaxial extrusion kneading method can also be used. In short, in this step, it is only necessary to give a perfluoroelastomer (FFKM) with a shearing force capable of separating the aggregated carbon nanotubes.

  Next, the second kneading step will be described with reference to FIG.

  As shown in FIG. 4, the first mixture 50 is wound around the first roll 10 while the first and second rolls 10 and 20 are rotated. The distance d between the first roll 10 and the second roll 20 is set to 1.5 mm, for example. A bank 54 is formed between the rolls 10 and 20. When PFA particles 90 are added into the bank 54 and the first and second rolls 10 and 20 are rotated, the second phase of PFA is contained in the first phase of perfluoroelastomer (FFKM) and carbon nanotubes. -A carbon fiber composite material dispersed in islands is obtained. This carbon fiber composite material is dispensed from the open roll 2. At the time of removal from the open roll 2, the carbon fiber composite material is uncrosslinked.

  After the second kneading step, a cross-linking agent can be added to the carbon fiber composite material using the open roll 2. The timing of blending the crosslinking agent may be during the first kneading step or during the second kneading step, but after the second kneading step so that crosslinking does not start during each kneading step. A crosslinking agent can be blended.

  Moreover, a 2nd kneading | mixing process can further include the 2nd penetration process performed with an open roll whose roll space | interval is 0.5 mm or less at 0 to 50 degreeC. The second threading process can be performed in the same manner as the first threading process described with reference to FIG. 3 in the first kneading process. By performing the second thinning step, the PFA particles can be further subdivided and dispersed in the carbon fiber composite material. By subdividing the PFA particles, there is an effect of preventing a relatively large PFA particle in the carbon fiber composite material from becoming a fracture starting point as a structural defect.

  In the present embodiment, an example in which the first thinning process and the second thinning process are performed has been described. However, the present invention is not limited to this, and depending on the amount of PFA particles, the first thinning process may be omitted, The carbon nanotubes can be defibrated and dispersed uniformly in the carbon fiber composite material by performing two thinning steps. When the blending amount of PFA particles is large (for example, blending amount exceeding 150 parts by mass with respect to 100 parts by mass of perfluoroelastomer (FFKM)), the carbon nanotubes are sufficiently solved only by the second thinning process. Since the fibers are not fibered, it is desirable to defibrate the carbon nanotubes in perfluoroelastomer (FFKM) in advance by the first thinning process.

  Finally, the molding process will be described with reference to FIGS.

  As shown in FIG. 5, a carbon fiber composite material containing an appropriate amount of the crosslinking agent dispensed from the open roll 2 is cut into a desired shape, for example, a ring shape, and placed in a compression mold 70. The compression molding die 70 has a lower die 74 and an upper die 72, and a carbon fiber composite material 60 cut out in a ring shape is disposed in a cavity formed between the lower die 74 and the upper die 72. Can do. The compression molding die 70 is attached to a vacuum press machine (not shown) so that the molding region including the cavity can be in a vacuum state.

The upper mold 72 is moved close to the lower mold 74 to compress the carbon fiber composite material 60, and the lower mold 74 and the upper mold 72 are heated to the primary vulcanization temperature, and the carbon fiber composite material is used for a predetermined time. 60 can be vulcanized. The cavity shape formed by the lower die 74 and the upper die 72 is a shape of a ball sheet in consideration of shrinkage after molding.

  Next, as shown in FIG. 6, the primary vulcanized molded product 62 taken out from the compression mold 70 can be placed on the table 104 in the oven 100 and heated to the secondary vulcanization temperature. it can. The furnace 102 in the oven 100 is set to a secondary vulcanization temperature, and the molded product 62 can be secondary vulcanized for a predetermined time. The primary vulcanization temperature, secondary vulcanization temperature, and vulcanization time can be set according to the type of perfluoroelastomer (FFKM).

  As shown in FIG. 7, after the secondary vulcanization, a secondary vulcanized molded product (ball sheet 30A) taken out from the oven can be obtained. In addition, the ball sheet 30A molded in a predetermined shape as described above can be further processed by cutting or polishing so as to be processed into a highly accurate molded product.

  The ball sheet 30A thus obtained has a small friction coefficient, excellent heat resistance, and excellent chemical resistance. In particular, the ball sheet manufacturing method does not use a high temperature like the conventional melt molding of tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA), so tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin ( Corrosive gas due to thermal decomposition of PFA) is not generated. Therefore, compared with the melt molding of tetrafluoroethylene / perfluoroalkyl vinyl ether-based fluororesin (PFA), the molding processability is excellent and the processing cost can be reduced. Moreover, the ball sheet 30A obtained in this manner is dense and free of voids because the first phase (matrix) is present between the PFA particles.

(VI) Ball Valve Examples of the ball valve include the floating ball valve in the first and second embodiments shown in FIGS. 8 and 9 and the trunnion type ball valve in the second embodiment shown in FIG. is there.

(First embodiment)
FIG. 8 is a longitudinal sectional view of the ball valve 10A according to the first embodiment.

  The ball valve 10A includes a ball 4 that is a valve body, bodies 1 and 2 that accommodate the ball 4, a stem 3 that rotates the ball 4, and an endless seat 30A that contacts the outer peripheral surface 4A of the ball 4. Have. The ball valve 10A is a so-called floating ball valve.

  The ball 4 has a through hole 4 </ b> B that forms a part of the flow path 12.

  The bodies 1 and 2 have a cavity 1A that rotatably accommodates the ball 4, an inlet 12A into which a fluid such as a polymerizable monomer gas flows, and an outlet 12B from which the fluid is discharged. The flow path 12 has a substantially circular outer peripheral surface centered on the central axis P, and is formed so as to extend substantially straight from the inlet 12A to the outlet 12B. The bodies 1 and 2 are composed of two members, and are composed of a body 1 constituting almost the whole of the cavity 1A and a body 2 generally called a body cap. An O-ring endless seal member 45 </ b> A is incorporated in a connecting portion between the body 1 and the body 2. The endless seal member 45 </ b> A is used as a static seal member, and can prevent the fluid from flowing out of the bodies 1 and 2 from the flow channel 12 even after the fluid is introduced into the flow channel 12. A cavity 1A having a larger diameter than the flow path 12 is formed between the outlet 12B and the inlet 12A.

  The ball sheet 30A has an endless shape, and comes into contact with the outer peripheral surface 4A of the ball 4 to seal the flow path 12 and the cavity 1A in a liquid-tight manner. The ball seat 30A can be provided at least on either the inlet 12A side or the outlet 12B side of the ball 4. In the present embodiment, ball sheets 30A and 30A having a circular outer shape are provided on both sides of the outer peripheral surface 4A on the inlet 12A side and the outlet 12B side. As shown in FIGS. 7 and 8, the ball sheets 30A and 30A have one end surface 31A facing the cavity 1A and abutting against the outer peripheral surface 4A of the ball 4, and the other end surface 32A abutting against the body 1 or body 2. It is arranged. The end surface 31 </ b> A has an arcuate vertical cross section that matches the shape of the outer peripheral surface 4 </ b> A of the ball 4. The end surface 32A is formed on a flat surface in accordance with the shape of the ball seat accommodating portion of the bodies 1 and 2. The ball seat 30 </ b> A has a communication hole 33 </ b> A communicating with the inlet 12 </ b> A and the outlet 12 </ b> B at the center, and penetrates along the central axis P.

  As the ball sheet 30A, the ball sheet 30A obtained by the manufacturing method described in the above (V) can be used. Even if the fluid is a polymerizable monomer such as butadiene gas, the ball sheet 30 </ b> A is less swelled and can maintain the sealing performance between the bodies 1 and 2 and the ball 4.

  The ball 4 is a substantially spherical body in which a through-hole 4B that penetrates from one surface to the other surface along the central axis P of the flow path 12 is formed. On the outer peripheral surface 4A of the ball 4, a pair of openings are formed in which both end portions of the through hole 4B are opened, and the annular ball sheets 30A, 30A are along the outer peripheral surface 4A at positions radially outside the opening. Are arranged in contact with each other. FIG. 8 shows a valve open state in which the through hole 4B of the ball 4 is arranged in line with the inlet 12A and the outlet 12B.

  A recess 4C is formed at the top of the ball 4, and the end of the stem 3 is inserted into the recess 4C. The recess 4C extends in a direction orthogonal to the central axis of the through hole 4B.

  The handle 9 is connected to the upper end of the stem 3 connected to the top of the ball 4.

  The stem 3 is rotatably supported through the body 1 and its lower end is inserted into the recess 4C of the ball 4 in the cavity 1A. By rotating the handle 9 around the rotation axis Q, the stem 3 and the ball 4 are rotated in the cavity 1A, and the communication state / non-communication state of the inlet 12A and the outlet 12B can be switched. That is, the flow path 12 can be opened and closed by the ball 4 by rotating the handle 9.

  When the handle 9 is turned and the ball 4 rotates around the rotation axis Q from the state shown in FIG. 8, the through hole 4B is orthogonal to the flow path 12 and closes between the inlet 12A and the outlet 12B. Between the ball 4 and the bodies 1 and 2, the ball ball sheet 30 </ b> A seals between the flow path 12 and the cavity 1 </ b> A.

(Second Embodiment)
FIG. 9 is a longitudinal sectional view of a ball valve 10B according to the second embodiment.

  The ball valve 10B includes a ball 4 that is a valve body, bodies 1 and 2 that accommodate the ball 4, a stem 3 that rotates the ball 4, an endless ball seat 30B that contacts the outer peripheral surface 4A of the ball 4, And an endless seat retainer 150 that holds the ball seat 30B. The ball valve 10B is a so-called floating ball valve. Since the basic configuration of the ball valve 10B other than the seat retainer 150 is substantially the same as that of the ball valve 10A, the same members are denoted by the same reference numerals, and redundant descriptions are omitted here.

  The ball seats 30B and 30B are disposed such that one end surface 31B faces the cavity 1A and contacts the outer peripheral surface 4A of the ball 4 and the other end surface 32B contacts the seat retainer 150. The ball seat 30 </ b> B is formed with a communication hole 33 </ b> B communicating with the inlet 12 </ b> A and the outlet 12 </ b> B at the center, and penetrates along the central axis P.

  Endless sheet retainers 150 and 150 hold the ball sheets 30B and 30B at predetermined positions in the cavity 1A. The sheet retainers 150 and 150 have their outer peripheral surfaces in contact with the inner peripheral surface of the cavity 1 </ b> A, and the inner peripheral surface is formed as a part of the flow path 12. The seat retainers 150 and 150 are disposed on the inflow port 12A side and the outflow port 12B side of the ball 4, hold the ball sheets 30B and 30B on the ball 4 side, respectively, and are interposed between the bodies 1 and 2 on the opposite side. The ball seats 30B and 30B are always urged toward the ball 4 side by seat springs 143 and 143 which are mounted elastic members.

  Endless seal members 45B and 45B are provided between the seat retainers 150 and 150 and the cavity 1A. The endless seal members 45B and 45B can be O-rings having a circular outer shape and a circular longitudinal section. The endless seal members 45B and 45B are mounted in grooves formed along the outer peripheral surfaces of the seat retainers 150 and 150, and the outer peripheral surfaces can contact and seal the inner peripheral surface of the cavity 1A. The endless seal members 45B and 45B are used as dynamic seal members, and even after the fluid is introduced into the flow path 12, the cavity 1A is maintained even when the seat retainers 150 and 150 move in the direction along the flow path 12. The sealability with the inner peripheral surface of the can be maintained.

  Even if the fluid is a polymerizable monomer such as butadiene gas, the ball sheet 30B is less swelled and can maintain the sealing performance between the bodies 1 and 2 and the ball 4.

(Third embodiment)
FIG. 10 is a perspective view in which a part of a ball valve 10C according to the third embodiment is cut away.

  The ball valve 10C includes a ball 4 that is a valve body, bodies 1 and 2 that accommodate the ball 4, a stem 3 that rotates the ball 4, an endless ball seat 30A that contacts the outer peripheral surface 4A of the ball 4, And an endless seat retainer 150 that holds the ball seat 30C. The ball valve 10C is a so-called trunnion type ball valve. Since the basic configuration of the ball valve 10C is substantially the same as that of the ball valve 10B, the same members are denoted by the same reference numerals, and redundant descriptions are omitted here.

  The ball 4 is different from the ball valve 10B in that stems 3 and 3 are arranged vertically along the rotation axis of the ball 4. The stem 3 disposed below the ball 4 is on the center side of the stem bearing 3B and is not shown. Further, the ball 4 is rotatable with respect to the cavity 1A via the stem bearings 3A and 3B arranged above and below.

  Endless seal members 45 </ b> C and 45 </ b> C are provided on the outer peripheral surface of the upper stem 3 with the body 1. Further, endless seal members 45E and 45E are provided between the sheet retainers 150 and 150 and the cavity 1A.

  Even if the fluid is a polymerizable monomer such as butadiene gas, the ball sheet 30 </ b> C is less swelled and can maintain the sealing performance between the bodies 1 and 2 and the ball 4.

As described above, according to the ball valves 10A, 10B, and 10C according to the first to third embodiments, the processing cost of the ball seats 30A, 30B, and 30C can be reduced to reduce the ball valves 10A, 10B, and 10C. Price competitiveness can be increased. Further, according to the ball valves 10A, 10B, and 10C according to the first to third embodiments, the ball valves 10A, 10B, and 10C are improved while the sealing performance between the bodies 1 and 2 and the ball 4 is improved. An increase in the opening / closing torque of can be suppressed.

(VII) Monomer Resistance Evaluation Test FIG. 11 is a schematic configuration diagram of an evaluation apparatus for evaluating the monomer resistance of a ball sheet according to an embodiment of the present invention. FIG. 12 is a schematic configuration diagram of an evaluation apparatus for evaluating the monomer resistance of a ball valve according to an embodiment of the present invention.

  Using a monomer resistance evaluation apparatus shown in FIG. 11, a ball sheet or a dumbbell-shaped test piece (hereinafter simply referred to as “test piece 126”) molded under the molding conditions of the ball sheet is placed in a thermostatic chamber 115. The monomer resistance evaluation test can be performed by exposing to a polymerizable monomer gas for a predetermined time.

  The gas cylinder 110 is connected by piping to a thermostatic chamber 115 purged with air through a flow rate adjusting valve 112 and a flow meter 114, and the piping in the thermostatic chamber 115 is a pressure resistant stainless steel in which a plurality of test pieces 126 are arranged via a heat exchanger 116. Connected to the lower end of the container 118. The pipe connected to the upper end of the pressure resistant stainless steel container 118 is connected to the exhaust line 124 outside the thermostat 115. A pressure gauge 120 and a flow rate adjustment valve 122 are provided in the exhaust line 124.

A monomer resistance evaluation test is specifically exemplified. First, the specific gravity (g / cm ³ ), volume (cm ³ ), and mass (g) of the test piece 126 before the evaluation test are measured. The test piece 126 may be formed into a ball sheet, or may be a strip-shaped test piece formed under the same processing conditions as the ball sheet. For example, liquefied butadiene gas (butadiene 100 vol%) as a polymerizable monomer is accommodated in the gas cylinder 110, and the flow rate adjustment valve 112 is opened and led to the thermostat 115. The butadiene gas heated to 80 ° C. by the heat exchanger 116 in the thermostat 115 fills the pressure resistant stainless steel container 118. The pressure in the pressure resistant stainless steel container 118 is set to 0.2 MPa to 0.3 MPa while checking with the pressure gauge 120. The exposure period is 360 hours (2 weeks) and 720 hours (4 weeks), and the specific gravity (g / cm ³ ), volume (cm ³ ), and mass (g) of the test piece 126 after each period is measured. The rate of change (%) from each measured value before the evaluation test is obtained. If the test piece 126 exposed to butadiene gas at 80 ° C. is excellent in monomer resistance (here, butadiene resistance), the rate of change due to swelling is small.

  Using the monomer resistance evaluation apparatus shown in FIG. 12, the ball valve 128 is placed in the thermostat 115 and exposed to a polymerizable monomer gas for a predetermined time to perform a monomer sheet evaluation test. be able to.

  The basic configuration of the evaluation apparatus is the same as that shown in FIG. In the thermostat 115, a plurality of ball valves 128 are connected to the piping instead of the pressure resistant stainless steel container 118. The ball valve 128 described with reference to FIGS. 8 to 10 can be used as the ball valve 128, and a ball seat is attached to the ball valve 128 at a predetermined position.

  Various conditions of the evaluation test are the same as those of the evaluation test apparatus described with reference to FIG. All the ball valves 128 are opened, and the ball seats in all the ball valves 128 are exposed to a polymerizable monomer such as butadiene gas at 80 ° C.

After a predetermined period from the start of the evaluation test, the thermostat 115 is opened, the torque at the time of opening and closing the ball valve 128 is measured, and air leakage from the closed ball valve 128 is confirmed. The air leakage from the ball valve 128 is caused by closing the compressed air in the ball valve 128, closing the ball valve 128, filling water into the inlet of the ball valve 128 (testing the outlet after the inlet test), Check whether the compressed air sealed in the cavity leaks. If the ball seat is excellent in monomer resistance, the opening / closing torque of the ball valve 128 after the evaluation test is hardly increased, and air leakage of compressed air does not occur.

  Although the embodiments of the present invention have been described in detail as described above, those skilled in the art can easily understand that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention.

  Hereinafter, the experiment and the result conducted in order to confirm the monomer resistance by embodiment of this invention are demonstrated.

(1) Production of Samples for Experiments 1 to 4 Samples used for Experiments 1 to 4 were produced by the following steps.

  Kneading step: 100 parts by mass (phr) of the elastomer shown in Table 1 was put into an open roll having a roll diameter of 6 inches (roll temperature: 10 to 20 ° C.) and wound around the roll (see FIG. 1).

  Next, fluororesin, carbon black (described as “CB” in each table) or carbon nanotube (described as “CNT” in each table) was added to the elastomer (see FIG. 2). At this time, the roll gap d was set to 1.5 mm. Further, a compounding agent such as an organic peroxide (peroxide) as a crosslinking agent was also added and kneaded.

  Thinning step: The elastomer mixture mixed with carbon nanotubes and the like is taken out from the roll, the roll gap d is narrowed from 1.5 mm to 0.3 mm, and the mixture is put into thinning to obtain a mixture ( (See FIG. 3). At this time, the surface speed ratio of the two rolls was set to 1.1. Thinning was repeated 5 times.

  Furthermore, the roll was set to a predetermined gap (1.1 mm) to dispense an uncrosslinked sample.

  Molding step: An uncrosslinked sample was put into a vacuum press and press-molded (primary vulcanization) at 160 ° C. for 10 minutes (see FIG. 5).

  Further, the sample was transferred to an oven and subjected to secondary vulcanization at 200 ° C. for 6 hours to obtain a peroxide-crosslinked sheet-like sample of Experiments 1 to 4 (see FIG. 6).

Each sample was subjected to a butadiene resistance evaluation test using the monomer resistance evaluation apparatus shown in FIG. Each condition of the evaluation test is
Butadiene gas: 100 vol%,
Temperature chamber and butadiene gas temperature: 80 ° C.
Atmospheric pressure in a pressure resistant stainless steel container: 0.2 MPa to 0.3 MPa,
Exposure time: 360 hours,
Met.

The butadiene resistance was evaluated by measuring the specific gravity (g / cm ³ ), volume (cm ³ ), and mass (g) of the sample before the evaluation test and after the elapse of the exposure time, and the rate of change ((after test-before test). ) / Before test × 100) (%) was calculated and listed in each table.

  First, as Comparative Example 1, a butadiene resistance evaluation test was performed on a sample of the same material as the current ball sheet. Comparative Example 1 was a tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA) manufactured by Daikin Co., which was AC5539 having excellent monomer resistance. The results of the evaluation test are shown in Table 1.

（実験１）
実験１として、エラストマーとフッ素樹脂からなるサンプルについて耐ブタジエン性評価試験を行った。比較例１−１は、エラストマーがダイキン社製の３元系ＦＫＭ（ビニリデンフロライド／テトラフルオロエチレン／ヘキサフルオロプロピレンの共重合体）のＧ９０２であり、フッ素樹脂がダイキン社製のＰＦＡのＡＣ５６００であった。比較例１−２は、エラストマーが同じくＧ９０２であり、フッ素樹脂がダイキン社製のＰＦＡのＡＣ５５３９であった。比較例１−３は、エラストマーがソルベイ社製のパーフルオロエラストマー（ＦＦＫＭ）のＰＦＲ９５ＨＴであり、フッ素樹脂がダイキン社製のＰＦＡのＡＣ５５３９であった。評価試験の結果は、表２に示した。なお、各材料の詳細は以下の通りであった。

(Experiment 1)
As Experiment 1, a butadiene resistance evaluation test was performed on a sample made of an elastomer and a fluororesin. In Comparative Example 1-1, the elastomer is G902 of ternary FKM (vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer) manufactured by Daikin, and the fluororesin is PFA AC5600 manufactured by Daikin. there were. In Comparative Example 1-2, the elastomer was also G902, and the fluororesin was PFA AC5539 made by Daikin. In Comparative Example 1-3, the elastomer was PFR95HT of perfluoroelastomer (FFKM) manufactured by Solvay, and the fluororesin was AC5539 of PFA manufactured by Daikin. The results of the evaluation test are shown in Table 2. The details of each material were as follows.

G902: Ternary FKM. Mooney viscosity ML _{(1 + 10)} 100 ° C. (center value) 50, fluorine content 70.5%, peroxide crosslinking.

PFR95HT: FFKM. ASTM D1646 Mooney viscosity ML _{(1 + 10)} 121 ° C. (center value) 75, fluorine content _> 72%, peroxide crosslinking.

AC-5600: fine powder of PFA. Average particle diameter (Laser diffraction) 20-60 μm, melting point (ASTM D3307) 303-313 ° C., melt index MFR (ASTM D3307) 1-30 g / 10 min, apparent density (JIS K6891) 0.5-0.9 g / ml.

実験１の結果によれば、比較例１−１〜比較例１−３のサンプルは、比較例１の現行品に比べて成形加工性に優れるが、耐ブタジエン性評価試験の変化率が大きかった。

According to the result of Experiment 1, the samples of Comparative Example 1-1 to Comparative Example 1-3 were excellent in molding processability compared with the current product of Comparative Example 1, but the rate of change in the butadiene resistance evaluation test was large. .

(Experiment 2)
As Experiment 2, the blending amount of the fluororesin in the sample of Comparative Example 1-1 of Experiment 1 was changed, and the influence of the blending amount of the fluororesin in the butadiene resistance evaluation test was examined. In Comparative Example 2-1 to Comparative Example 2-4, the elastomer was ternary FKM G902 made by Daikin, and the fluororesin was PFA AC5600 made by Daikin. The results of the evaluation test are shown in Table 3.

実験２の結果によれば、比較例２−１〜比較例２−４のサンプルは、フッ素樹脂の配合量の増加に伴って耐ブタジエン性評価試験の変化率が小さくなった。

According to the results of Experiment 2, in the samples of Comparative Examples 2-1 to 2-4, the rate of change in the butadiene resistance evaluation test decreased with an increase in the blending amount of the fluororesin.

(Experiment 3)
As Experiment 3, a butadiene resistance evaluation test was performed on a sample in which carbon black or carbon nanotube was blended with an elastomer. In Comparative Examples 3-1 to 3-6, the elastomer is ternary FKM G902 made by Daikin, the carbon black is HAF grade, the carbon nanotubes have an average diameter of 18.6 nm, and the rigidity is 3.1. It was a multi-walled carbon nanotube. The results of the evaluation test are shown in Table 4.

実験３の結果によれば、比較例３−１〜比較例３−６のサンプルは、フッ素樹脂の配合量の増加に伴って耐ブタジエン性評価試験の変化率が小さくなった。

According to the results of Experiment 3, in the samples of Comparative Examples 3-1 to 3-6, the rate of change in the butadiene resistance evaluation test decreased with an increase in the blending amount of the fluororesin.

(Experiment 4)
As Experiment 4, a butadiene resistance evaluation test was performed on a sample in which carbon black or carbon nanotube was blended using FFKM as an elastomer. The elastomer is a perfluoroelastomer (FFKM) manufactured by Solvay, with a Mooney viscosity (ML _{1 + 4} 100 ° C.) of 25, a TR-10 value of −30 ° C., and a peak value of loss tangent (tan δ). Was −15 ° C. The carbon black of Comparative Example 4-2 to Comparative Example 4-4 is FEF grade, the carbon nanotube of Comparative Example 4-5 to Comparative Example 4-7 is a multi-walled carbon nanotube having an average diameter of 68 nm, Comparative Example 4-8 to Comparative The carbon nanotube of Example 4-10 was a multi-walled carbon nanotube having an average diameter of 18.6 nm and a rigidity of 3.1. The results of the evaluation test are shown in Table 5.

According to the result of Experiment 4, the rate of change in the butadiene resistance evaluation test was smaller for the samples of Comparative Examples 4-1 to 4-10 than for the sample of Experiment 3 using ternary FKM. Also,
The sample using the carbon nanotubes of Comparative Example 4-5 and Comparative Example 4-7 has a rate of change in the butadiene resistance evaluation test rather than the sample using the carbon black of Comparative Example 4-2 to Comparative Example 4-4. It has become smaller. Further, the samples using the carbon nanotubes of Comparative Examples 4-8 to 4-10 changed the butadiene resistance evaluation test more than the samples using the carbon nanotubes of Comparative Examples 4-5 to 4-7. The rate has decreased. The sample of Comparative Example 4-8, which had the smallest rate of change in the butadiene resistance evaluation test, had the same rate of change in the butadiene resistance evaluation test as the current product of Comparative Example 1.

1 body, 1A cavity, 2 body, 3, stem, 3A, 3B stem bearing, 4 ball, 4A outer peripheral surface, 4B through hole, 4C recess, 10 first roll, 10A, 10B valve, 12 flow path, 12A flow Inlet, 12B outlet, 20 second roll, 30 perfluoroelastomer (FFKM), 30A ball sheet, 31A, 31B, 32A, 32B end face, 33A, 33B communication hole, 34 bank, 36 mixture, 45A, 45B, 45C 45E endless seal member, 50 first mixture, 54 banks, 60 carbon fiber composite material, 62 primary vulcanized molded product, 70 mold, 72 upper mold, 74 lower mold, 80 carbon nanotube, 90 fluororesin, 100 ovens, 102
Furnace chamber, 104 table, 143 seat spring, 150 seat retainer, F load, P center axis, Q rotation axis

Claims (5)

An endless ball seat that contacts and seals with the outer surface of a ball valve in which a ball having a through hole is rotatably mounted in the body,
A ball sheet comprising a perfluoroelastomer (FFKM) matrix containing carbon nanotubes having an average diameter of 2 nm to 100 nm and tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA). In claim 1,
A tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA) is 5 to 150 parts by mass with respect to 100 parts by mass of perfluoroelastomer (FFKM). In claim 1 or 2,
The compounding amount of the carbon nanotube is 0.5 to 50 parts by mass with respect to 100 parts by mass of the perfluoroelastomer (FFKM). Tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA) and perfluoroelastomer A ball sheet, which is 0.2 to 47.6 parts by mass with respect to 100 parts by mass of a matrix combined with (FFKM). In any one of Claims 1-3,
The carbon nanotube is a multi-walled carbon nanotube having an average diameter of 9 nm to 20 nm,
The multi-walled carbon nanotube contains 0.5 to 50 parts by mass with respect to 100 parts by mass of perfluoroelastomer (FFKM),
A tetrafluoroethylene / perfluoroalkyl vinyl ether fluororesin (PFA) contains a swelling inhibitor comprising a sulfur-containing compound and an amine compound.   A ball valve using the ball seat according to claim 1.

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