Conductive components for tires and non-pneumatic tires

Abstract

The objective is to provide a conductive material for tires that can improve electrostatic properties. [Solution] A conductive member for tires comprising an insulating layer containing a thermoplastic resin or thermoplastic elastomer and a conductive layer bonded to the insulating layer, wherein when the conductive member for tires is applied to a non-pneumatic tire and the non-pneumatic tire is driven for 20,000 km on a durability drum tester, the conductive layer has a surface resistivity of 1 × 10⁻¹⁰ before and after driving. 10 It is a conductive material for tires with a impedance of Ω or less.

Description

[Technical Field]

[0001] This invention relates to a conductive member for tires and a non-pneumatic tire. [Background technology]

[0002] In recent years, tires that do not require pressurized air to be filled inside have been proposed to prevent punctures.

[0003] For example, Patent Document 1 discloses a non-pneumatic tire comprising an annular tread portion that contacts the road surface, an annular inner circumference portion located inside the tread portion in the tire radial direction and having conductivity, and a plurality of connecting portions connecting the tread portion and the inner circumference portion, wherein the tread portion comprises a first portion that contacts the road surface and has conductivity, and a second portion located on the inner circumference side of the first portion, and the second portion, the connecting portions, and the inner circumference portion are formed of a resin containing carbon short fibers. Furthermore, Patent Document 2 discloses a non-pneumatic tire comprising an annular tread portion that contacts the road surface, an annular inner circumference portion located inside the tread portion in the tire radial direction and connected to a conductive wheel, and a plurality of connecting portions connecting the tread portion and the inner circumference portion, wherein the tread portion comprises a first portion that contacts the road surface and is conductive, and a second portion located inside the first portion in the tire radial direction, and the second portion, the connecting portions, and the inner circumference portion are formed of a resin containing carbon black. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2017-001602 [Patent Document 2] Japanese Patent Publication No. 2017-218132 [Overview of the project] [Problems that the invention aims to solve]

[0005] In the above-mentioned Patent Documents 1 and 2, conductive materials such as carbon short fibers and carbon black are incorporated into tire frame members such as connecting members to improve the conductivity of the tire frame members and thereby improve the electrostatic properties of non-pneumatic tires. As described in Patent Documents 1 and 2 above, incorporating conductive materials into tire frame members can improve conductivity, but on the other hand, it can significantly affect the physical properties of non-pneumatic tires. While the influence of such material incorporation on the physical properties of non-pneumatic tires can be suppressed to some extent by controlling the amounts of various materials used, there are limits to how much this influence can be suppressed. Therefore, other means are needed to improve the electrostatic properties of non-pneumatic tires.

[0006] Therefore, the objective of this disclosure is to provide a conductive material for tires that can solve the problems of the above-mentioned conventional technology and improve electrostatic properties. Furthermore, this disclosure aims to provide a non-pneumatic tire with improved electrostatic properties. [Means for solving the problem]

[0007] The gist of the present invention, which solves the above problems, is as follows.

[0008] [1] A conductive member for tires comprising an insulating layer containing a thermoplastic resin or thermoplastic elastomer and a conductive layer bonded to the insulating layer, When the aforementioned conductive material for tires is applied to a non-pneumatic tire and the non-pneumatic tire is driven for 20,000 km on a durability drum tester, the surface resistivity of the conductive layer before and after driving is 1 × 10⁻⁶. 10 A conductive material for tires with a impedance of Ω or less. The conductive material for tires described in [1] above can improve the electrostatic properties when applied to tires.

[0009] [2] The dynamic modulus measured under conditions of temperature 30°C, dynamic strain 3%, and frequency 15Hz was 3 × 10⁻⁶. 7 Pa or more 2×108 The conductive member for a tire according to [1], which is below Pa. The conductive member for a tire according to [2] above can improve the chargeability when applied to a tire and is excellent in durability.

[0010] [3] The conductive member for a tire according to [1] or [2], wherein when a checkerboard test conforming to JIS-K5600-5-6 is carried out, none of the grids are peeled off. The conductive member for a tire according to [3] above can improve the chargeability when applied to a tire and is more excellent in the bonding strength between the insulating layer and the conductive layer.

[0011] [4] The conductive member for a tire according to any one of [1] to [3], wherein the conductive layer has a thickness of 0.01 to 1 mm. The conductive member for a tire according to [4] above can improve the chargeability when applied to a tire and is more excellent in the bonding strength between the insulating layer and the conductive layer.

[0012] [5] The conductive member for a tire according to any one of [1] to [4], wherein the conductive layer is made of conductive ink, conductive tape, conductive fiber, or conductive rubber. The conductive member for a tire according to [5] above can improve the chargeability when applied to a tire.

[0013] [6] A non-pneumatic tire comprising an inner cylinder externally mounted on a wheel, an outer cylinder surrounding the inner cylinder from the outer side in the tire radial direction, a plurality of connecting members arranged along the tire circumferential direction between the inner cylinder and the outer cylinder for connecting the two cylinders, and a tread member provided on the outer side in the tire radial direction of the outer cylinder, A non-pneumatic tire, wherein at least one of the plurality of connecting members is a conductive member for a tire according to any one of [1] to [5]. The non-pneumatic tire according to [6] above has improved chargeability.

[0014] [7] A non-pneumatic tire comprising: an inner cylinder fitted to a wheel; an outer cylinder surrounding the inner cylinder from the outside in the tire radial direction; a plurality of connecting members arranged between the inner cylinder and the outer cylinder along the tire circumferential direction for connecting the two cylinders; and a tread member provided on the outer side of the outer cylinder in the tire radial direction, In some of the multiple connecting members, the material constituting the some connecting members is different from the material constituting the other connecting members. When a non-pneumatic tire was driven 20,000 km on a durability drum testing machine, the surface resistivity before and after driving was 1 × 10⁻⁶ 10 Non-pneumatic tires with a weight of Ω or less. The non-pneumatic tires described in [7] above have improved electrostatic properties. [Effects of the Invention]

[0015] According to this disclosure, it is possible to provide a conductive member for tires that can improve electrostatic properties. Furthermore, this disclosure makes it possible to provide non-pneumatic tires with improved electrostatic properties. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram showing the configuration of a non-pneumatic tire according to one embodiment of the present disclosure, as viewed from the side of the tire. [Modes for carrying out the invention]

[0017] The conductive member for tires and the non-pneumatic tire of this disclosure will be described in detail below based on their embodiments.

[0018] <Definition> The compounds described herein may be derived in part or in whole from fossil resources, from biological resources such as plant resources, or from recycled resources such as used tires. They may also be derived from a mixture of two or more of fossil resources, biological resources, and recycled resources.

[0019] In this specification, "skeletal member" means a member that constitutes the skeleton of a non-pneumatic tire, more specifically, a member that supports the tread member from the inside to the outside of the tire in order to maintain the shape of the tire tread. Skeletal members include, for example, the inner cylinder, outer cylinder, and connecting members (spoke structure) in a non-pneumatic tire (hereinafter, these may be collectively referred to as "connecting members, etc.").

[0020] <Conductive material for tires> The conductive member for tires in this embodiment is A conductive member for tires comprising an insulating layer containing a thermoplastic resin or thermoplastic elastomer, and a conductive layer bonded to the insulating layer, When the aforementioned conductive material for tires is applied to a non-pneumatic tire and the non-pneumatic tire is driven for 20,000 km on a durability drum tester, the surface resistivity of the conductive layer before and after driving is 1 × 10⁻⁶. 10 It is characterized by being less than or equal to Ω. The above-mentioned conductive material for tires can conduct electricity through the conductive layer, and therefore, when applied to tires, it can improve the static charge properties of the tires.

[0021] The conductive member for tires of this embodiment can be applied as a component of a non-pneumatic tire. The structure of a non-pneumatic tire will be described later, but a non-pneumatic tire includes a skeletal member that supports the tread member from the inside outward in order to maintain the shape of the tire tread. The skeletal member includes an inner cylinder that is fitted onto the wheel, an outer cylinder that surrounds the inner cylinder from the outside in the tire radial direction, and connecting members that connect the two cylinders, which are arranged in multiple quantities along the tire circumferential direction between the inner and outer cylinders. The conductive member for tires of this embodiment is preferably applied to the skeletal member in a non-pneumatic tire, and more specifically, it is preferably applied to at least one of the connecting members, the inner cylinder, and the outer cylinder.

[0022] The conductive material for tires in this embodiment has a dynamic modulus of 3 × 10⁻¹⁰ when measured under the conditions of a temperature of 30°C, torsional mode, dynamic strain of 3%, and frequency of 15 Hz. 7 Pa or more 2×108 It is preferably below Pa. The dynamic elastic modulus of the conductive member for a tire is 3×10 7 Pa or more and 2×10 8 Pa or less, and it has excellent durability. The dynamic elastic modulus of the conductive member for a tire is 4×10 7 Pa or more is more preferable, and 5×10 7 Pa or more is even more preferable. Further, the dynamic elastic modulus of the conductive member for a tire is 1×10 8 Pa or less is more preferable, and 9×10 7 Pa or less is even more preferable. These upper and lower limits can be arbitrarily combined. Incidentally, the dynamic elastic modulus can be measured using a dynamic viscoelasticity tester.

[0023] (Insulating layer) The insulating layer included in the conductive member for a tire of the present embodiment contains a thermoplastic resin or a thermoplastic elastomer. The insulating layer can be obtained by molding a resin composition containing a thermoplastic resin or a thermoplastic elastomer.

[0024] Examples of the thermoplastic resin include polyester resin, polyamide resin, polyolefin resin, polystyrene resin, etc. Among these, from the viewpoints of durability and cost, polyester resin is preferable.

[0025] The polyester resin is a resin having an ester bond in the main chain. The polyester resin is not particularly limited, but crystalline polyester is preferable. As the crystalline polyester, aromatic polyester can be used. The aromatic polyester can be formed from, for example, an aromatic dicarboxylic acid or its ester-forming derivative and an aliphatic diol. Examples of the aromatic polyester include polyethylene terephthalate, polybutylene terephthalate, polystyrene terephthalate, polyethylene naphthalate, polybutylene naphthalate, etc., and polybutylene terephthalate is preferable.

[0026] One example of the aromatic polyester is polybutylene terephthalate derived from terephthalic acid and / or dimethyl terephthalate and 1,4-butanediol. Furthermore, a dicarboxylic acid component such as isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid, 5-sulfoisophthalic acid, or ester-forming derivatives thereof, and a diol with a molecular weight of 300 or less {for example, ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, decamethylene glycol, and other aliphatic diols}. The polyester may be derived from alicyclic diols such as 1,4-cyclohexanedimethanol and tricyclodecanedimethylol, xylylene glycol, bis(p-hydroxy)diphenyl, bis(p-hydroxyphenyl)propane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane, bis[4-(2-hydroxy)phenyl]sulfone, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 4,4'-dihydroxy-p-terphenyl, 4,4'-dihydroxy-p-quarterphenyl, or other aromatic diols, or copolymerized polyesters using two or more of these dicarboxylic acid and diol components in combination. It is also possible to copolymerize polyfunctional carboxylic acid components with three or more functions, polyfunctional oxyacid components, and polyfunctional hydroxy components in a range of 5 mol% or less.

[0027] Commercially available polyester resins can also be used, such as the "DuraNex" series from Polyplastics Corporation (e.g., 2000, 2002, etc.), the NovaDuran series from Mitsubishi Engineering Plastics Corporation (e.g., 5010R5, 5010R3-2, etc.), the "Toraycon" series from Toray Industries, Inc. (e.g., 1401X06, 1401X31, 1401X70, etc.), and the "Planac" series from Toyobo Co., Ltd. (e.g., BT-1000).

[0028] The polyamide resin is a resin having an amide bond (-NHCO-) ​​in its main chain. Examples of the polyamide resin include polycapramide (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecaneamide (nylon-11), polylauryl lactam (nylon-12), polyethylenediamine adipamide (nylon-2,6), polytetramethylene adipamide (nylon-4,6), polyhexamethylene adipamide (nylon-6,6), and polyhexamethylene sevacamide (nylon-6,1 Examples include aliphatic polyamides such as polyhexamethylene dodecamide (nylon-6,12), polyoctamethylene adipamide (nylon-8,6), and polydecamethylene adipamide (nylon-10,8), and crystalline aromatic polyamides obtained by polycondensation reactions of aromatic diamines such as metaxylenediamine and paraxylenediamine with dicarboxylic acids or derivatives thereof, such as adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, and isophthalic acid. Among these, nylon-6, nylon-6,6, and nylon-12 are preferred, with nylon-12 being more preferred.

[0029] As the polyamide resin, commercially available products can be used, for example, UBESTA manufactured by Ube Industries (e.g., 3014U, 3020U, etc.) and VESTAMID manufactured by Daicel Evonix (e.g., L1600, L1700, etc.).

[0030] The polyolefin resin has a main chain of olefin polymers such as ethylene, propylene, and 1-butene. Examples of the polyolefin resin include polyethylene, polypropylene, polybutene, cycloolefin resins, and copolymers of these resins. Among these, polyethylene, polypropylene, and ethylene-propylene copolymers are preferred, and polypropylene and ethylene-propylene copolymers are more preferred.

[0031] As the aforementioned polyolefin resin, commercially available products can be used, for example, Prime PP (registered trademark) manufactured by Prime Polymer Co., Ltd., and Novatec PP (registered trademark) and Wintec (registered trademark) manufactured by Nippon Polypropylene Co., Ltd.

[0032] The polystyrene resin is a polymer of styrene. Commercially available polystyrene resins can be used, such as Zarec® manufactured by Idemitsu Kosan Co., Ltd., Toyo Styrene® manufactured by Toyo Styrene Co., Ltd., and Sebian manufactured by Daicel Polymer Co., Ltd.

[0033] Furthermore, the insulating layer may include a thermoplastic elastomer. Here, thermoplastic elastomers and thermoplastic resins are polymer compounds that soften and flow as the temperature rises, and become relatively hard and strong when cooled. In this specification, polymer compounds that soften and flow as the temperature rises, become relatively hard and strong when cooled, and have rubber-like elasticity are referred to as thermoplastic elastomers, while polymer compounds that soften and flow as the temperature rises, become relatively hard and strong when cooled, and do not have rubber-like elasticity are referred to as thermoplastic resins. Furthermore, "thermoplastic elastomer" refers to a thermoplastic resin material having hard segments and soft segments in its molecule. More specifically, it refers to a thermoplastic resin material consisting of an elastic polymer compound, comprising a copolymer having a crystalline, high-melting-point hard segment and an amorphous, low-glass transition-temperature soft segment. Note that the thermoplastic elastomer in this invention does not include vulcanized rubbers such as natural rubber or synthetic rubber.

[0034] Examples of the aforementioned thermoplastic elastomers include polyester-based thermoplastic elastomers (TPC), polyamide-based thermoplastic elastomers (TPA), polyolefin-based thermoplastic elastomers (TPO), and polystyrene-based thermoplastic elastomers (TPS). Among these, polyester-based thermoplastic elastomers (TPC) are preferred from the viewpoint of durability and cost. The aforementioned polyester thermoplastic elastomer (TPC) is an elastic polymer compound, and refers to a thermoplastic resin material comprising a copolymer having a crystalline polymer constituting a hard segment with a high melting point and an amorphous polymer constituting a soft segment with a low glass transition temperature, wherein the main chain of the polymer constituting the hard segment has an ester bond.

[0035] Aromatic polyesters can be used as the crystalline polyester that forms the hard segments of the polyester-based thermoplastic elastomer (TPC). Aromatic polyesters can be formed, for example, from aromatic dicarboxylic acids or their ester-forming derivatives and aliphatic diols. Examples of aromatic polyesters that form hard segments include polyethylene terephthalate, polybutylene terephthalate, polystyrene terephthalate, polyethylene naphthalate, and polybutylene naphthalate, with polybutylene terephthalate being preferred. One suitable aromatic polyester for forming the hard segment is polybutylene terephthalate derived from terephthalic acid and / or dimethyl terephthalate and 1,4-butanediol. Furthermore, a dicarboxylic acid component such as isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid, 5-sulfoisophthalic acid, or ester-forming derivatives thereof, and ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, decamethylene glycol The polyester may be derived from diol components such as 1,4-cyclohexanedimethanol, tricyclodecanedimethylol, xylylene glycol, bis(p-hydroxy)diphenyl, bis(p-hydroxyphenyl)propane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane, bis[4-(2-hydroxy)phenyl]sulfone, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 4,4'-dihydroxy-p-terphenyl, or 4,4'-dihydroxy-p-quarterphenyl, or a copolymer polyester obtained by using two or more of these dicarboxylic acid and diol components in combination.

[0036] Examples of polymers that form the soft segments of the polyester-based thermoplastic elastomer (TPC) include polymers selected from aliphatic polyethers and aliphatic polyesters. Examples of the aliphatic polyether include poly(ethylene oxide) glycol, poly(propylene oxide) glycol, poly(tetramethylene oxide) glycol, poly(hexamethylene oxide) glycol, copolymers of ethylene oxide and propylene oxide, ethylene oxide addition polymers of poly(propylene oxide) glycol, copolymers of ethylene oxide and tetrahydrofuran, and the like. Examples of the aliphatic polyester include poly(ε-caprolactone), polyenanthractone, polycapryloractone, polybutylene adipate, and polyethylene adipate. Among these aliphatic polyethers and aliphatic polyesters, poly(tetramethylene oxide) glycol, ethylene oxide addition polymers of poly(propylene oxide) glycol, poly(ε-caprolactone), polybutylene adipate, polyethylene adipate, etc. are preferred from the viewpoint of the elastic properties of the resulting copolymer.

[0037] The polyester-based thermoplastic elastomer can be synthesized by copolymerizing a polymer that forms a hard segment and a polymer that forms a soft segment using a known method. Alternatively, commercially available polyester-based thermoplastic elastomers can be used, such as the "Perprene" series from Toyobo Co., Ltd. (P30B, P40B, P40H, P-46D01, P55B, P70B, P90B, P120B, P150B, P280B, P450B, P150M, S1001, S2001, S5001, S6001, S9001, etc.) and the "Hytrel" series from Toray DuPont (e.g., 3046, 5557, 5577, 5577R-07, 6347, 4047, 4767, 4767N, 4777, etc.).

[0038] The polyamide-based thermoplastic elastomer (TPA) is an elastic polymer compound, and is a thermoplastic resin material comprising a copolymer having a crystalline, high-melting-point hard segment and an amorphous, low-glass transition-temperature soft segment, wherein the main chain of the polymer constituting the hard segment has an amide bond (-CONH-). Examples of the polyamide-based thermoplastic elastomer include materials in which at least the polyamide constitutes a crystalline, high-melting-point hard segment, and other polymers (e.g., polyester, polyether, etc.) constitute an amorphous, low-glass transition-temperature soft segment.

[0039] The crystalline polyamides constituting the hard segment of the polyamide-based thermoplastic elastomer (TPA) include polycapramide (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecaneamide (nylon-11), polylauryl lactam (nylon-12), polyethylenediamine adipamide (nylon-2,6), polytetramethylene adipamide (nylon-4,6), polyhexamethylene adipamide (nylon-6,6), and polyhex Examples include aliphatic polyamides such as methylene sebaamide (nylon-6,10), polyhexamethylene dodecamide (nylon-6,12), polyoctamethylene adipamide (nylon-8,6), and polydecamethylene adipamide (nylon-10,8), and crystalline aromatic polyamides obtained by polycondensation reactions of aromatic diamines such as metaxylenediamine and paraxylenediamine with dicarboxylic acids or derivatives thereof, such as adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, and isophthalic acid. Among these, nylon-6, nylon-6,6, and nylon-12 are preferred, with nylon-12 being more preferred.

[0040] Examples of polymers that constitute the soft segment of the polyamide-based thermoplastic elastomer (TPA) include polymers selected from polymethylene and aliphatic polyethers. Examples of the aliphatic polyether include poly(ethylene oxide) glycol, poly(propylene oxide) glycol, poly(tetramethylene oxide) glycol, poly(hexamethylene oxide) glycol, copolymers of ethylene oxide and propylene oxide, ethylene oxide addition polymers of poly(propylene oxide) glycol, copolymers of ethylene oxide and tetrahydrofuran, and the like.

[0041] The polyamide-based thermoplastic elastomer can be synthesized by copolymerizing the polymer forming the hard segment and the polymer forming the soft segment using a known method. Alternatively, commercially available polyamide-based thermoplastic elastomers can be used, such as the "UBESTA XPA" series from Ube Industries (e.g., XPA9063X1, XPA9055X1, XPA9048X2, XPA9048X1, XPA9040X1, XPA9040X2, XPA9044, XPA9048, XPA9055, etc.) and the "Vestamid" series from Daicel Eponic (e.g., E40-S3, E47-S1, E47-S3, E55-S1, E55-S3, EX9200, E50-R2).

[0042] The aforementioned polyolefin-based thermoplastic elastomer (TPO) is an elastic polymer compound, and refers to a thermoplastic resin material comprising a copolymer having a crystalline, high-melting-point hard segment and an amorphous, low-glass transition-temperature soft segment, wherein the polymer constituting the hard segment is a polyolefin such as polypropylene or polyethylene. Examples of the polyolefin-based thermoplastic elastomer include materials in which at least the polyolefin constitutes a hard segment that is crystalline and has a high melting point, and the polyolefin and other olefins constitute a soft segment that is amorphous and has a low glass transition point.

[0043] Examples of polyolefins that form the hard segments of the polyolefin-based thermoplastic elastomer include polypropylene, isotactic polypropylene, polyethylene, and poly-1-butene. Examples of polymers constituting the soft segment of the polyolefin-based thermoplastic elastomer include ethylene-propylene copolymer, propylene-1-hexene copolymer, propylene-4-methyl-1-pentene copolymer, propylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-4-methyl-pentene copolymer, ethylene-1-butene copolymer, 1-butene-1-hexene copolymer, and 1-butene-4-methyl-pentene.

[0044] The polyolefin-based thermoplastic elastomer can be synthesized by copolymerizing the polymer constituting the hard segment and the polymer constituting the soft segment using a known method. Furthermore, commercially available polyolefin-based thermoplastic elastomers can be used, such as Prime TPO® from Prime Polymer, and Tuffmer® and Notio® from Mitsui Chemicals.

[0045] The polystyrene-based thermoplastic elastomer (TPS) refers to an elastic polymer compound, a thermoplastic resin material comprising a copolymer having a polymer constituting a hard segment and a polymer constituting an amorphous soft segment with a low glass transition temperature, wherein the polymer constituting the hard segment is polystyrene or a polystyrene derivative. The polystyrene-based thermoplastic elastomer is not particularly limited, but examples include copolymers in which polystyrene constitutes a hard segment and an amorphous polymer constitutes a soft segment with a low glass transition temperature (e.g., polyethylene, polybutadiene, polyisoprene, hydrogenated polybutadiene, hydrogenated polyisoprene, poly(2,3-dimethyl-butadiene), etc.).

[0046] The polystyrene-based thermoplastic elastomer can be synthesized by copolymerizing the polymer constituting the hard segment and the polymer constituting the soft segment by known methods such as block copolymerization. Furthermore, commercially available polystyrene-based thermoplastic elastomers can be used, such as Toughprene® and Toughtec® manufactured by Asahi Kasei Corporation, or Septon® manufactured by Kuraray Co., Ltd.

[0047] The insulating layer may contain additives in addition to the resin components such as the thermoplastic resin and thermoplastic elastomer mentioned above. Examples of additives included in the insulating layer include weather-resistant anti-aging agents, heat-resistant anti-aging agents, moisture-resistant heat additives, antistatic agents, lubricants, crystal nucleating agents, tackifiers, anti-fogging agents, mold release agents, plasticizers, fillers, pigments, dyes, fragrances, and flame retardants. Among these, weather-resistant anti-aging agents, heat-resistant anti-aging agents, and moisture-resistant heat additives are preferred, and weather-resistant anti-aging agents and heat-resistant anti-aging agents are even more preferred. The inclusion of weather-resistant anti-aging agents and heat-resistant anti-aging agents in the insulating layer improves the stability of the insulating layer, and conductive components for tires containing such insulating layers can maintain the desired properties over a long period of time. The total content of these additives is preferably 20 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of the resin component.

[0048] The weather-resistant anti-aging agent is an additive that improves the weather resistance of the resin composition, and benzotriazole compounds and amine compounds (hindered amine compounds) are preferred as the weather-resistant anti-aging agent. Examples of the benzotriazole compounds include 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole, benzenepropanoic acid and ester compounds of 3-(2H-benzotriazole-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy(C7-9 side chain and linear alkyl), octyl 3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole-2-yl)phenyl]propionate and 2-ethylhexyl-3-[3-tert- A mixture of butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol, methyl-3-(3-(2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxyphenyl)propionate / Reaction products of polyethylene glycol 300: 2-(2H-benzotriazol-2-yl)-p-cresol, 2-(2H-benzotriazol-2-yl)-4-6-bis(1-methyl-1-phenylethyl)phenol, 2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol, 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-butyl) Examples include tramethylbutylphenol, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol], 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol, 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimidomethyl)-5-methylphenyl]benzotriazole, and 2,2'-methylenebis[6-(benzotriazol-2-yl)-4-tert-octylphenol]. Examples of the amine compounds include bis(1,2,2,6,6-pentamethyl-4-piperidinyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, a mixture of bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, and bis(2,2,6,6-tetramethyl-4-piperidyl) ) Sebacate, N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-N,N'-diformylhexamethylenediamine, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], tetrakis(1,2,2,6,6 -Pentamethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, reaction product of 1,2,2,6,6-pentamethyl-4-piperidiol and β,β,β',β'-tetramethyl-2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diethanol, 2,2,6,6-Te Examples include reaction products of tramethyl-4-piperidiol and β,β,β',β'-tetramethyl-2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diethanol, bis(1-undecanoxy-2,2,6,6-tetramethylpiperidine-4-yl) carbonate, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, and 2,2,6,6-tetramethyl-4-piperidyl methacrylate. The inclusion of a weather-resistant anti-aging agent in the insulating layer improves its weather resistance, allowing the conductive component for tires containing such an insulating layer to maintain the desired properties over a long period. The amount of weather-resistant anti-aging agent added is preferably in the range of 1 to 5 parts by mass per 100 parts by mass of the resin component.

[0049] The aforementioned heat-resistant aging inhibitor is an additive that has the effect of improving the heat resistance of the insulating layer, and a phenolic compound (hindered phenolic compound) is preferred as the heat-resistant aging inhibitor. Examples of the phenolic compound include 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane, 2,4-di-tert-butyl-6-methylphenol, 1,6-hexanediol-bis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(3, 5-di-tert-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 3,9-bis-[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)-propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5] Undecane, triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 2,2'-butylidenebis(4,6-di-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenol acrylate, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di Examples include -tert-pentylphenyl acrylate, 4,4'-thiobis(3-methyl-6-tert-butylphenol), 2-tert-butyl-4-methylphenol, 2,4-di-tert-butylphenol, 2,4-di-tert-pentylphenol, 4,4'-thiobis(3-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), bis-[3,3-bis-(4'-hydroxy-3'-tert-butylphenyl)-butanoic acid]-glycol ester, and N,N'-hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanamide]. The inclusion of a heat-resistant anti-aging agent in the insulating layer improves its heat resistance, allowing the conductive component for tires containing such an insulating layer to maintain desired properties over a long period. The amount of heat-resistant anti-aging agent added is preferably in the range of 1 to 5 parts by mass per 100 parts by mass of the resin component.

[0050] The aforementioned moisture-resistant heat additive is an additive that improves the moisture-resistant heat properties of the insulating layer. Preferably, the moisture-resistant heat additive is a carbodiimide compound or an epoxy compound, with epoxy compounds being more preferred. Specifically, the carbodiimide compound can be any compound having one or more carbodiimide groups in its molecule. Examples include monofunctional carbodiimide compounds such as N,N'-diisopropylcarbodiimide, N,N'-di(o-toluyl)carbodiimide, N,N'-dicyclohexylcarbodiimide, and N,N'-bis(2,6-diisopropylphenyl)carbodiimide; difunctional carbodiimide compounds such as p-phenylene-bis(2,6-xylylcarbodiimide), p-phenylene-bis(t-butylcarbodiimide), p-phenylene-bis(mesitylcarbodiimide), tetramethylene-bis(t-butylcarbodiimide), and cyclohexane-1,4-bis(methylene-t-butylcarbodiimide); and polyfunctional carbodiimide compounds such as condensates of isocyanate monomers. Among these, polyfunctional carbodiimide compounds are preferred. Here, a polyfunctional carbodiimide compound refers to a compound having two or more carbodiimide groups. Examples of such polyfunctional carbodiimide compounds include those commonly known by trade names such as Carbodilite LA-1 (manufactured by Nisshinbo Co., Ltd.), Carbodilite HMV-8CA (manufactured by Nisshinbo Co., Ltd.), Carbodilite HMV-15CA (manufactured by Nisshinbo Co., Ltd.), Elastostab H01 (manufactured by Nisshinbo Co., Ltd.), and Stabaxol P (manufactured by Rhein Chemie). One or more of these carbodiimide compounds can be used. Furthermore, as the epoxy compound, specifically, are epoxidized soybean oil, epoxidized linseed oil, phenyl glycidyl ether, allyl glycidyl ether, tert-butylphenyl glycidyl ether, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexyl carboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3',4'-epoxy-6'-methylcyclohexyl carboxylate, 2,3-epoxycyclohexylmethyl-3',4'-epoxycyclohexyl carboxylate, 4-(3,4-epoxy Xy-5-methylcyclohexyl)butyl-3',4'-epoxycyclohexyl carboxylate, 3,4-epoxycyclohexyl ethylene oxide, cyclohexylmethyl-3,4-epoxycyclohexyl carboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6'-methylsilohexyl carboxylate, bisphenol A diglycidyl ether, tetrabromobisphenol A glycidyl ether, diglycidyl ester of phthalate, diglycidyl ester of hexahydrophthalate, bis-epoxydicyclopentadie Nyl ether, bis-epoxyethylene glycol, bis-epoxycyclohexyl adipate, butadiene diepoxide, tetraphenylethylene epoxide, octyl epoxytalate, epoxidized polybutadiene, 3,4-dimethyl-1,2-epoxycyclohexane, 3,5-dimethyl-1,2-epoxycyclohexane, 3-methyl-5-tert-butyl-1,2-epoxycyclohexane, octadecyl-2,2-dimethyl-3,4-epoxycyclohexyl carboxylate, n-butyl-2,2-dimethyl-3,4-epoxycyclo Hexyl carboxylate, cyclohexyl-2-methyl-3,4-epoxycyclohexyl carboxylate, n-butyl-2-isopropyl-3,4-epoxy-5-methylcyclohexyl carboxylate, octadecyl-3,4-epoxycyclohexyl carboxylate, 2-ethylhexyl-3',4'-epoxycyclohexyl carboxylate, 4,6-dimethyl-2,3-epoxycyclohexyl-3',4'-epoxycyclohexyl carboxylate, 4,5-epoxy tetrahydrophthalic anhydride, 3-tert-butyl-4,Examples include 5-epoxy tetrahydrophthalic anhydride, diethyl-4,5-epoxy-cis-1,2-cyclohexyl dicarboxylate, and di-n-butyl-3-tert-butyl-4,5-epoxy-cis-1,2-cyclohexyl dicarboxylate. One or more of these epoxy compounds can be used. The inclusion of a moisture- and heat-resistant additive in the insulating layer improves its moisture- and heat resistance, allowing the conductive component for tires containing such an insulating layer to maintain the desired properties over a long period of time. The amount of moisture- and heat-resistant additive added is preferably in the range of 1 to 15 parts by mass per 100 parts by mass of the resin component.

[0051] The method for forming the insulating layer is not particularly limited, and it can be obtained by injection molding or the like using a thermoplastic resin or thermoplastic elastomer. Furthermore, if it contains components other than a thermoplastic resin or thermoplastic elastomer, it can be obtained by kneading a resin composition containing a thermoplastic resin or thermoplastic elastomer and various other components, and then molding the resin composition. Furthermore, the method for preparing the resin composition is not particularly limited. Additives may be added after mixing the resin components, or the resin components and additives may be mixed at the same time. Multiple resin components with additives already added may be mixed, or resin components with additives added may be mixed with resin components without additives.

[0052] (Conductive layer) The conductive member for tires in this embodiment includes a conductive layer. The conductive layer is bonded to the insulating layer. The material of the conductive layer is not particularly limited as long as it is conductive.

[0053] The conductive layer is preferably 0.01 to 1 mm thick. Having the conductive layer thickness within this range improves electrostatic properties and allows for a conductive tire component with superior bonding strength between the insulating layer and the conductive layer. From the viewpoint of bonding strength between the insulating layer and the conductive layer, the conductive layer thickness is more preferably 0.8 mm or less, and even more preferably 0.6 mm or less. From the viewpoint of conductivity, it is more preferably 0.02 mm or more, and even more preferably 0.03 mm or more.

[0054] The bonding strength between the conductive layer and the insulating layer can be measured in accordance with JIS-K5600-5-6. When a grid test is performed in accordance with JIS K5600, the conductive ink layer 6 preferably has a ratio of 20 / 25 or higher, more preferably 23 / 25 or higher, and most preferably (number of squares that have not peeled) / (total number of squares) is 25 / 25, that is, no squares in the grid have peeled.

[0055] The conductive layer, when subjected to a 20,000 km run on a non-pneumatic tire in a durability drum tester, showed a surface resistivity of 1 × 10⁻⁶ before and after the run. 10 It is preferable that the resistance is Ω or less. When a non-pneumatic tire is driven for 20,000 km on a durability drum tester, the surface resistivity of the conductive layer before and after driving is 1 × 10⁻⁶. 10 If the resistance is less than Ω, the electrostatic charge before and after travel is improved. Furthermore, the surface resistivity before and after travel is 1 × 10⁻⁶ 0 It may be Ω or higher. The conductive layer, when subjected to a 20,000 km run on a non-pneumatic tire in a durability drum tester, had a surface resistivity of 1 × 10⁻⁶ before running. 8 It is more preferable that it be less than or equal to Ω, and 1 × 10 7 It is even more preferable that the resistivity is less than or equal to Ω. Furthermore, when a non-pneumatic tire is driven for 20,000 km on a durability drum test machine, the conductive layer has a surface resistivity of 1 × 10⁻⁶ after driving. 8 It is more preferable that it be less than or equal to Ω, and 1 × 10 7 It is even more preferable that it be less than or equal to Ω. The above upper and lower limits can be combined in any way. The surface resistivity of the conductive layer was measured using a tester under room temperature (23°C).

[0056] The conductive layer is preferably made of conductive ink, conductive tape, conductive fibers, or conductive rubber. Among these, the conductive layer is more preferably made of conductive ink or conductive rubber due to reasons such as superior bonding strength between the insulating layer and the conductive layer.

[0057] [Conductive ink] The conductive ink preferably contains a binder resin, conductive powder, and a solvent. That is, the conductive layer formed with the conductive ink may consist of a binder resin containing conductive powder. Examples of commercially available conductive inks include Polycalm PTP-G1501 (manufactured by Pluscoat Co., Ltd.), Airrace ESM500cb (manufactured by Edogawa Gosei Co., Ltd.), Airrace EMI768N (manufactured by Edogawa Gosei Co., Ltd.), Polycalm G2028 (manufactured by Pluscoat Co., Ltd.), Polycalm PCS-S2117 (manufactured by Pluscoat Co., Ltd.), and Polycalm PCS-1949CG (manufactured by Pluscoat Co., Ltd.).

[0058] Examples of binder resins include resin pastes such as polyurethane resin, polyester resin, acrylic resin, ethylene-vinyl acetate copolymer, silicone resin, polyimide resin, polyester resin, and polyamide resin. Among these, polyurethane resin, polyester resin, or acrylic resin is preferred as the binder resin in order to ensure adhesion and flexibility to thermoplastic resin or thermoplastic elastomer. These binder resins may be used individually or in combination of two or more.

[0059] Examples of conductive powders that can be used include carbon black, graphite, and metallic conductive materials. These conductive powders may be used individually or in combination of two or more types.

[0060] The conductive ink preferably contains carbon black and / or graphite as conductive powder. The carbon black and graphite can contribute to the conductivity of the conductive layer.

[0061] The carbon black mentioned above is not particularly limited and includes, for example, furnace carbon such as HAF, ISAF, and SAF grades, as well as channel black, thermal black, and acetylene black. These carbon blacks may be used individually or in combination of two or more types.

[0062] Furthermore, conductive ink may also contain a metallic conductive material as a conductive powder. Examples of metallic conductive materials include elemental metals and metallic compounds. Examples of metallic conductive materials include copper, iron, nickel, palladium, platinum, gold, silver, aluminum, tungsten, and alloys thereof. Preferably, the conductive ink does not contain metallic conductive materials. If the conductive ink contains metallic conductive materials, these materials can become failure points when a conductive layer is formed using the conductive ink. By not including these metallic conductive materials, the conductive layer exhibits superior scratch resistance and maintenance of conductivity after deformation, resulting in a conductive component for tires that is superior in scratch resistance and electrostatic properties.

[0063] The solvent is not particularly limited as long as it can dissolve the binder resin. Among these, high-boiling point solvents such as toluene, ethylene glycol, ethylene glycol monoether, and N-methyl-2-pyrrolidone (NMP) are preferred. These solvents may be used individually or in combination of two or more.

[0064] [Conductive tape] The conductive tape is not limited to any conductive tape having high electrical conductivity. Examples of conductive tapes include copper tape, metal tapes such as aluminum tape, and carbon tape.

[0065] Commercially available conductive tape can also be used. Examples of commercially available conductive tapes include No. 8303 and No. 8323 manufactured by Teraoka Seisakusho.

[0066] [Conductive Fibers] Examples of conductive fibers include conductive metal-plated fibers, which are fibers plated with a conductive metal, and fibers impregnated with a conductive polymer. Examples of conductive metals include silver, alumina, gold, and copper, with silver being preferred from the viewpoint of high conductivity. The fibers are not particularly limited, but polyester fibers and nylon fibers can be used from the viewpoint of excellent durability.

[0067] Commercially available conductive fibers can also be used. Examples of commercially available conductive fibers include No. 1825 manufactured by Teraoka Seisakusho.

[0068] [Conductive rubber] The conductive rubber is not limited to any conductive rubber, but it is preferable to include a diene-based rubber and carbon black. In conductive rubber containing carbon black, the carbon black can provide conductivity.

[0069] Examples of the diene rubber include natural rubber (NR), synthetic isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), and chloroprene rubber (CR). The diene rubber may be used alone or as a blend of two or more types.

[0070] In conductive rubber, the carbon black content is preferably 50 parts by mass or more per 100 parts by mass of diene rubber. When the carbon black content is 50 parts by mass or more per 100 parts by mass of diene rubber, the electrical resistance of the conductive rubber becomes sufficiently low, resulting in excellent conductivity. Furthermore, from the viewpoint of excellent conductivity, the carbon black content is preferably 55 parts by mass or more, and more preferably 60 parts by mass or more, per 100 parts by mass of diene rubber. In addition, to suppress the reduction in strength, the carbon black content is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 80 parts by mass or less, per 100 parts by mass of diene rubber. These upper and lower limits can be combined arbitrarily.

[0071] The carbon black mentioned above is not particularly limited and examples include HAF, ISAF, and SAF grade carbon black. These carbon blacks may be used individually or in combination of two or more types.

[0072] The conductive rubber may contain other components in addition to the diene-based rubber and carbon black mentioned above. Examples of other components include antioxidants, crosslinking agents, vulcanization accelerators, softeners, and zinc oxide. These other components can be used as appropriate, as long as they do not interfere with the conductivity of the conductive rubber.

[0073] (intervening layer) The conductive member for tires in this embodiment may include an intervening layer between the insulating layer and the conductive layer, if necessary. By providing an intervening layer between the insulating layer and the conductive layer, the bonding strength between the insulating layer and the conductive layer can be improved. The intervening layer is not limited to, but examples include an adhesive layer and an intervening rubber layer. These layers are preferably provided, for example, when the conductive layer is made of conductive rubber.

[0074] The adhesive layer serves to bond the insulating layer and the conductive layer. While not limited to these, the adhesive layer is preferably made of a urethane-based adhesive or an epoxy-based adhesive, and more preferably a urethane-based adhesive. When the adhesive layer is made of a urethane-based adhesive, the bonding strength between the insulating layer and the conductive layer tends to be superior.

[0075] Commercially available urethane adhesives can be used. Examples of such urethane adhesives include "UT100B" and "EP171" from Cemedyne Corporation, "560" from 3M Corporation, "NIPPORAN 2304" and "NIPPORAN 3114" from Tosoh Corporation, "DA3146" from Nogawa Chemical Co., Ltd., "TAKENATE XL3052-20" and "TAKERIGHT 4010 / 4000B" from Mitsui Chemicals, Inc., and "7411" and "7542" from LORD Co., Ltd.

[0076] Commercially available epoxy adhesives can be used. Examples of such epoxy adhesives include "Metlweld," "Silver chip," and "T-88" from SYSTEM THREE, "ARARALDITE RT30," "ARARALDITE 2013," "ARARALDITE 2014," and "ARARALDITE 2015" from Huntsman, "EAE-30CL," "E-05CL," "U-10FL," and "EA-E00CL" from Henkel, "3500" and "3600" from Alteco, "DP190" from 3M, and "AP209" and "AP400ED" from Toagosei Co., Ltd.

[0077] The intervening rubber layer is a rubber layer having a different composition from the conductive rubber described above. More specifically, it is preferable that the intervening rubber layer has a lower carbon black content than the conductive layer. Since the conductive layer needs to have excellent conductivity, it contains a relatively large amount of carbon black. When rubber has a relatively high carbon black content, the adhesion to the insulating layer tends to be low. Therefore, by providing an intervening rubber layer between the conductive layer and the insulating layer, the bonding strength can be increased.

[0078] Various rubber compositions containing at least a rubber component can be used for the intervening rubber layer, and it is preferable to form the intervening rubber layer from vulcanized rubber obtained by vulcanizing the rubber composition. The rubber composition can be produced, for example, by mixing a rubber component made of natural rubber or synthetic rubber (butadiene rubber, styrene-butadiene rubber, isoprene rubber, chloroprene rubber, etc.) with fillers such as carbon black and silica, antioxidants, crosslinking agents such as stearic acid, sulfur, and peroxides, crosslinking accelerators, etc., and then kneading, heating, extruding, etc.

[0079] (Method for manufacturing conductive materials for tires) The conductive component for tires of this embodiment can be manufactured by kneading a thermoplastic resin and an arbitrary component to prepare a resin composition, injection molding the resin composition using a known method to form an insulating layer, and then forming a conductive layer on the formed insulating layer. Furthermore, if necessary, a surface treatment may be applied to the surface of the insulating layer that is joined to the conductive layer.

[0080] <Airless tires> A non-pneumatic tire according to one embodiment of the present disclosure (hereinafter referred to as the "non-pneumatic tire according to the first embodiment") is A non-pneumatic tire comprising: an inner cylinder fitted to the wheel; an outer cylinder surrounding the inner cylinder from the outside in the tire radial direction; a plurality of connecting members arranged between the inner cylinder and the outer cylinder along the tire circumferential direction, connecting the two cylinders together; and a tread member provided on the outer side of the outer cylinder in the tire radial direction, The present invention is characterized in that at least one of the multiple connecting members is a conductive member for tires according to this embodiment. The above-mentioned non-pneumatic tire has improved electrostatic properties because it is equipped with the conductive member for tires according to this embodiment.

[0081] While the electrostatic properties can be improved if at least one of the multiple connecting members is the conductive tire material of this embodiment, from the viewpoint of further reducing electrostatic properties, it is preferable that the proportion of the connecting members that are the conductive tire material of this embodiment is 2% or more, more preferably 5% or more, and particularly preferable that 100%, i.e., all connecting members, are the conductive tire material of this embodiment. However, from the viewpoint of productivity and durability, the proportion of the connecting members that are the conductive tire material of this embodiment may be 20% or less, or even 10% or less. The proportion of all connecting members that are conductive members for tires according to this embodiment can be calculated using the following formula. (Percentage of conductive members for tires in this embodiment) = (Number of conductive members for tires in this embodiment) ÷ (Total number of connecting members)

[0082] Here, the structure of the non-pneumatic tire (hereinafter sometimes simply referred to as "tire") of this disclosure will be explained with reference to Figure 1. Figure 1 is a schematic diagram showing the configuration of the non-pneumatic tire 1 of this disclosure, as viewed from the side of the tire. In the drawings used in the following explanation, the scale has been appropriately changed to make each component recognizable.

[0083] As shown in Figure 1, the non-pneumatic tire 1 of this disclosure comprises an inner cylinder 2 fitted onto a wheel (not shown), an outer cylinder 3 surrounding the inner cylinder 2 from the radially outer side of the tire, and a plurality of elastically deformable connecting members 4 arranged between the inner cylinder 2 and the outer cylinder 3 along the circumferential direction of the tire, which connect the inner cylinder 2 and the outer cylinder 3 so that they can be displaced relative to each other. A tread member 5 is fitted onto the outer circumferential surface of the outer cylinder 3. This non-pneumatic tire 1 is used on wheelchairs (especially electric wheelchairs), bicycles, motorcycles, golf carts, automobiles, etc. (hereinafter, these are collectively referred to simply as vehicles).

[0084] Here, the inner cylinder 2, outer cylinder 3, and tread member 5 are formed in an annular shape, and their respective central axes are located on a common axis. In this specification, this common axis is referred to as the central axis O, and the direction along the central axis O is referred to as the tire width direction. Furthermore, in a side view from the tire width direction, the direction that circles around the central axis O is referred to as the tire circumferential direction, and the direction perpendicular to this central axis O is referred to as the tire radial direction.

[0085] The inner cylinder 2 is attached to the vehicle's axle (not shown) via a wheel. The wheel and axle can be made of metal materials such as aluminum, aluminum alloy, or steel. The central axes of the inner cylinder 2 and the outer cylinder 3 are coaxial with the central axis O. The inner cylinder 2, the outer cylinder 3, and the connecting member 4 are positioned such that their respective centers in the tire width direction coincide.

[0086] In this embodiment, the inner cylinder 2, outer cylinder 3, and connecting member 4 may be integrally formed from a resin composition. This allows the inner cylinder 2, outer cylinder 3, and connecting member 4 to be molded by injection molding, making them suitable for mass production. The inner cylinder 2, outer cylinder 3, and connecting member 4 may each be formed as separate components.

[0087] The tread member 5 may be formed from, for example, vulcanized rubber obtained by vulcanizing a rubber composition including natural rubber, or from a thermoplastic material. Examples of thermoplastic materials include polyurethane resin, polyolefin resin, polyvinyl chloride resin, and polyamide resin. From the viewpoint of abrasion resistance, it is preferable to form the tread member 5 from vulcanized rubber. In this embodiment, an adhesive layer (not shown) may be provided between the outer cylinder 3 and the tread member 5 to interpose the joining of the outer cylinder 3 and the tread member 5. A commercially available adhesive can be used for the adhesive layer. For example, cyanoacrylate adhesives or epoxy adhesives can be used, and specifically, Aron Alpha EXTRA 2000 (manufactured by Toagosei Co., Ltd.) can be used, but it is not limited to these.

[0088] The connecting member 4 is formed as a curved rectangular plate, with its front and back surfaces facing the tire circumferential direction and its sides facing the tire width direction. The connecting member 4 is made of an elastically deformable material and connects the outer circumferential surface of the inner cylinder 2 and the inner circumferential surface of the outer cylinder 3 in a manner that allows for relative elastic displacement. Multiple connecting members 4 are arranged at equal intervals in the tire circumferential direction. In Figure 1, there are 30 connecting members 4, but the number of connecting members 4 in the non-pneumatic tire 1 of this embodiment is not limited to this.

[0089] Each of the multiple connecting members 4 has an inner portion 4a connected to the inner cylinder 2 and an outer portion 4b connected to the outer cylinder 3. The inner portion 4a and the outer portion 4b are connected to each other at the center of the connecting member 4 in the tire radial direction. When driving, the connecting member 4 elastically deforms under load, absorbing vibrations transmitted from the ground to the vehicle.

[0090] In the non-pneumatic tire 1 of this disclosure, the inner cylinder 2, outer cylinder 3, and connecting member 4 of the non-pneumatic tire 1 may be collectively referred to as the skeletal member, and it is preferable that the inner cylinder 2, outer cylinder 3, and connecting member 4 are made of a resin composition described later. Furthermore, in the non-pneumatic tire 1 according to this embodiment, different resin compositions may be used for the inner cylinder 2, outer cylinder 3, and connecting member 4 that constitute the skeletal member.

[0091] Furthermore, in addition to the connecting member 4, the non-pneumatic tire 1 according to the first embodiment may also have an inner cylinder 2 which is the conductive member 6 for the tire according to this embodiment, an outer cylinder 3 which is the conductive member 6 for the tire according to this embodiment, or both the inner cylinder 2 and the outer cylinder 3 which are the conductive member 6 for the tire according to this embodiment.

[0092] In another embodiment, the non-pneumatic tire (hereinafter referred to as the "non-pneumatic tire according to the second embodiment") is A non-pneumatic tire comprising: an inner cylinder fitted to the wheel; an outer cylinder surrounding the inner cylinder from the outside in the tire radial direction; a plurality of connecting members arranged between the inner cylinder and the outer cylinder along the tire circumferential direction, connecting the two cylinders together; and a tread member provided on the outer side of the outer cylinder in the tire radial direction, In some of the multiple connecting members, the material constituting the some connecting members is different from the material constituting the other connecting members. When a non-pneumatic tire was driven 20,000 km on a durability drum testing machine, the surface resistivity before and after driving was 1 × 10⁻⁶ 10 It is characterized by being less than or equal to Ω. The above-mentioned non-pneumatic tires have improved electrostatic properties.

[0093] In the second embodiment, when the non-pneumatic tire is driven for 20,000 km on a durability drum testing machine, the surface resistivity before and after driving is 1 × 10⁻⁶. 10 It is less than Ω. When a non-pneumatic tire is driven for 20,000 km on a durability drum test machine, the surface resistivity before and after driving is 1 × 10⁻⁶. 10 If the resistance is less than Ω, the electrostatic charge before and after travel is improved. Furthermore, the surface resistivity before and after travel is 1 × 10⁻⁶ 0 It may be Ω or higher. In the second embodiment, when the non-pneumatic tire is driven for 20,000 km on a durability drum testing machine, the surface resistivity before driving is 1 × 10⁻⁶. 8 It is more preferable that it be less than or equal to Ω, and 1 × 10 7 It is even more preferable that it be less than or equal to Ω. Furthermore, in the non-pneumatic tire according to the second embodiment, when the non-pneumatic tire is driven for 20,000 km on a durability drum test machine, the surface resistivity after driving is 1 × 10⁻⁶ 8 It is more preferable that it be less than or equal to Ω, and 1 × 10 7 It is even more preferable that it be less than or equal to Ω. The above upper and lower limits can be combined in any way. The surface resistivity was measured using a tester at room temperature (23°C).

[0094] In the non-pneumatic tire according to the second embodiment, in some of the connecting members (hereinafter, for convenience, referred to as "first connecting members"), the material constituting the some connecting members is different from the material constituting the connecting members other than the some connecting members (hereinafter, for convenience, referred to as "second connecting members"). In other words, among the n connecting members of the non-pneumatic tire, the material constituting a connecting members is different from the material constituting the n - a connecting members. Note that 1 ≤ a < n / 2. By making the materials of some of the plurality of connecting members different in this way, for example, some of the connecting materials can be made to have excellent conductivity, thereby improving the charging property of the non-pneumatic tire.

[0095] The number of the first connecting members is less than half of the total number of the connecting members. Let the total number of the connecting members of the non-pneumatic tire be n, and the number of the first connecting members be a. Then a is an integer such that 1 ≤ a < n / 2. Also, if the number of the second connecting members is b, then b = n - a.

[0096] In a preferred embodiment, the first connecting member is made of a material having higher conductivity than the second connecting member. That is, the first connecting member is more excellent in conductivity than the second connecting member. Also, in other words, the first connecting member has a lower surface resistivity than the second connecting member. When the non-pneumatic tire is run on a durability drum tester for 20,000 km, the surface resistivity of the first connecting member before and after running is preferably 1×10 10 Ω or less, more preferably 1×10 8 Ω or less, and even more preferably 1×10 7 Ω or less. Note that the surface resistivity of the first connecting member may be 1×10 0 Ω or more before and after the running. Also, when the non-pneumatic tire is run on a durability drum tester for 20,000 km, the surface resistivity of the second connecting member before and after running is higher than that of the first connecting member, and can be, for example, 1×10 19 Ω or more. The surface resistivity is a value measured using a tester in an environment at room temperature (23°C).

[0097] The first and second connecting members are preferably made of a resin composition. The resin composition contains resin components and preferably a thermoplastic resin or a thermoplastic elastomer. These thermoplastic resins and thermoplastic elastomers are the same as those used for the thermoplastic resin and thermoplastic elastomer of the insulating layer, and the descriptions of thermoplastic resins and thermoplastic elastomers in the section on the insulating layer can be used as reference. The resin composition may also contain additives. The descriptions of additives can also be used as reference for the descriptions of additives in the section on the insulating layer.

[0098] The resin composition constituting the first connecting member may contain a material that provides conductivity. Examples of such conductive materials include carbon black, acetylene black, graphite, carbon fibers, carbon nanotubes, graphite, metal particles, metal fibers, metal-coated fibers, conductive polymers, conductive polymer-coated fibers, and metal nanowires. These may be used individually or in combination of two or more.

[0099] The resin composition constituting the first connecting member more preferably contains carbon black. The inclusion of carbon black in the first connecting member results in a connecting member with excellent conductivity. In the resin composition constituting the first connecting member, the carbon black content is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and even more preferably 20 parts by mass or more, per 100 parts by mass of the resin component. Alternatively, the carbon black content may be 50 parts by mass or less per 100 parts by mass of the resin component.

[0100] The second connecting member is not particularly limited in its constituent materials, as long as it contains the thermoplastic resin and thermoplastic elastomer described above. Preferably, the second connecting member does not contain conductive materials such as carbon black, acetylene black, graphite, carbon fibers, carbon nanotubes, graphite, metal particles, metal fibers, metal-coated fibers, conductive polymers, conductive polymer-coated fibers, or metal nanowires. This is because while the inclusion of such materials can improve conductivity, it reduces the strength of the connecting member.

[0101] The non-pneumatic tire according to the second embodiment can be manufactured, for example, by injection molding a resin composition constituting the second connecting member to form a skeletal member, and then injection molding the first connecting member to bond the skeletal member and the first connecting member. [Examples]

[0102] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to the following examples.

[0103] <Example 1> (1) Fabrication of resin skeletal members Using polyester thermoplastic elastomer (TPC, manufactured by Toray Celanese Co., Ltd., product name "Hytrel 5557"), resin skeletal components (connecting members, inner cylinder, and outer cylinder) for a 12-inch size are manufactured by injection molding at 260°C. Next, a polyester-based conductive ink is applied to the connecting member of the fabricated skeletal member, and the conductive ink is dried at 80°C to form a conductive layer on the connecting member, which is the insulating layer.

[0104] (2) Fabrication of rubber ring tread member On the other hand, a rubber composition is prepared by mixing 30 parts by mass of butadiene rubber and 70 parts by mass of natural rubber (100 parts by mass of rubber components) with 50 parts by mass of carbon black and appropriate amounts of additives such as vulcanizing chemicals, vulcanization accelerators, and softeners. After molding the composition into a predetermined shape, it is vulcanized at 160°C for 15 minutes to produce a 12-inch rubber annular tread member. Chemlok 7701 (manufactured by Road Japan Inc.) is applied to the inner circumferential surface of the tread member and subjected to chlorination treatment.

[0105] (3) Manufacturing of non-pneumatic tires The tread member and the resin frame member are placed inside an envelope with the inner circumferential surface of the tread member (the surface that has been treated with chlorine) and the outer circumferential surface of the resin frame member (the surface of the outer cylinder) in contact. The envelope is then placed in an autoclave (manufactured by Hanyuda Iron Works) and, under conditions of a temperature of 130°C and a pressure of 0.7 MPa, the pressure inside the envelope is reduced to -0.01 MPa (compared to atmospheric pressure) for 30 minutes to bond the tread member and the resin frame member, thereby producing a 145 / 80R12 size non-pneumatic tire.

[0106] <Example 2> A non-pneumatic tire is manufactured in the same manner as in Example 1, except that the polyester-based conductive ink is replaced with an acrylic-based conductive ink.

[0107] <Example 3> A non-pneumatic tire was prepared in the same manner as in Example 1, except that conductive ink was replaced with conductive rubber. The conductive rubber was prepared by mixing 100 parts by mass of styrene-butadiene rubber (100 parts by mass of rubber component) with 60 parts by mass of carbon black, and appropriate amounts of additives such as vulcanizing chemicals, vulcanization accelerators, and softeners to create a rubber composition. After molding it into a predetermined shape, it was vulcanized at 160°C for 15 minutes. Conductive rubber was bonded using a urethane-based adhesive (manufactured by Road Corporation, product name "7542A / B") and formed on the connecting member, which serves as an insulating layer.

[0108] <Comparative Example 1> A non-pneumatic tire was manufactured in the same manner as in Example 1, except that conductive ink was not applied and a conductive layer was not formed.

[0109] <Measurement Method and Evaluation Method> (1) Thickness of the conductive layer For Examples 1 and 2, the thickness of the conductive layer was measured using calipers. For Example 3 and Comparative Example 1, the thickness of the conductive layer was measured using calipers. The measurement results are shown in Table 1.

[0110] (2) Conductivity (surface resistivity) For Example 1 and Comparative Example 2, the surface resistivity of the conductive layer of the obtained non-pneumatic tire was measured using a Custom CDM-2000D tester at room temperature (23°C) under a constant load, both before and after 20,000 km of driving on a drum durability tester at 60 km / h. If no conductive layer was formed, the surface resistivity of the connecting member surface was measured. For Example 3 and Comparative Example 1, the surface resistivity of the conductive layer of the obtained non-pneumatic tires was measured using a Custom CDM-2000D tester at room temperature (23°C) under a constant load, both before and after 20,000 km of driving on a drum durability tester at 60 km / h. In cases where no conductive layer was formed, the surface resistivity of the connecting member surface was measured. The evaluation results are shown in Table 1.

[0111] (3) Bonding strength between the insulating layer and the conductive layer For Example 1 and Comparative Example 2, the bond strength between the insulating layer and the conductive layer will be evaluated by a grid test in accordance with JIS K5600 after the fabricated non-pneumatic tires have been driven for 20,000 km. The bond strength will be evaluated according to the following criteria. For Example 3 and Comparative Example 1, the bond strength between the insulating layer and the conductive layer was evaluated by a grid test in accordance with JIS K5600 after the fabricated non-pneumatic tires were driven for 20,000 km. The bond strength was evaluated according to the following criteria. A: 25 / 25 B: 20 / 25~24 / 25 C: Less than 20 / 25 The evaluation results are shown in Table 1.

[0112] [Table 1]

[0113] *1 Polyester-based conductive ink: A conductive ink primarily composed of polyester resin, manufactured by Edogawa Gosei Co., Ltd., product name "Eleas ESM500cb", containing carbon black. *2 Acrylic conductive ink: A conductive ink primarily composed of acrylic resin, manufactured by Pluscoat Co., Ltd., product name "PCS-1949CG", containing carbon black. *3 OL: Overload, the resistance was too high to measure. In other words, it is highly charged.

[0114] Table 1 shows that a non-pneumatic tire equipped with the conductive member for tires of this embodiment exhibits excellent conductivity, resulting in improved electrostatic properties. [Industrial applicability]

[0115] According to the present invention, it is possible to provide a conductive member for tires that can improve electrostatic properties. Furthermore, this disclosure makes it possible to provide non-pneumatic tires with improved electrostatic properties.

[0116] [Contribution to the United Nations-led Sustainable Development Goals (SDGs)] The SDGs have been proposed to realize a sustainable society. One embodiment of the present invention is considered to be a technology that can contribute to "No. 12: Responsible Consumption and Production" and "No. 13: Take urgent action to combat climate change and its impacts." [Explanation of symbols]

[0117] 1: Non-pneumatic tires 2: Inner cylinder 3: Outer cylinder 4: Connecting member 4a: Inner part 4b:Outer part 5: Tread material O: Central axis D: Diameter in the radial direction of the tire 6: Conductive components for tires

Claims

1. A conductive member for tires comprising an insulating layer containing a thermoplastic resin or thermoplastic elastomer, and a conductive layer bonded to the insulating layer, When the aforementioned conductive material for tires is applied to a non-pneumatic tire and the non-pneumatic tire is driven for 20,000 km on a durability drum test machine, the surface resistivity of the conductive layer before and after driving is 1 × 10⁻⁶. １０ A conductive material for tires with a impedance of Ω or less.

2. The dynamic modulus of elasticity measured under the conditions of a temperature of 30°C, torsional mode, dynamic strain of 3%, and frequency of 15 Hz was 3 × 10⁻⁶. ７ Pa or more 2×10 ８ A conductive member for tires according to claim 1, wherein the pressure is Pa or less.

3. The conductive layer is a conductive member for tires according to claim 1, wherein, when a grid test is performed in accordance with JIS-K5600-5-6, no grid cells peel off.

4. The conductive member for tires according to claim 1, wherein the conductive layer has a thickness of 0.01 to 1 mm.

5. The conductive layer is made of conductive ink, conductive tape, conductive fibers, or conductive rubber, as described in claim 1.

6. A non-pneumatic tire comprising: an inner cylinder fitted to the wheel; an outer cylinder surrounding the inner cylinder from the outside in the tire radial direction; a plurality of connecting members arranged between the inner cylinder and the outer cylinder along the tire circumferential direction, connecting the two cylinders together; and a tread member provided on the outer side of the outer cylinder in the tire radial direction, A non-pneumatic tire in which at least one of the plurality of connecting members is the conductive member for tire described in claim 1.

7. A non-pneumatic tire comprising: an inner cylinder fitted to the wheel; an outer cylinder surrounding the inner cylinder from the outside in the tire radial direction; a plurality of connecting members arranged between the inner cylinder and the outer cylinder along the tire circumferential direction, connecting the two cylinders together; and a tread member provided on the outer side of the outer cylinder in the tire radial direction, In some of the multiple connecting members, the material constituting the some connecting members is different from the material constituting the other connecting members. When a non-pneumatic tire is driven 20,000 km on a durability drum testing machine, the surface resistivity before and after driving is 1 × 10⁻⁶. １０ Non-pneumatic tires with a weight of Ω or less.

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