Non-pneumatic tires

Abstract

The present invention provides a non-pneumatic tire that can maintain adhesion between the resin skeletal member and the rubber tread member even after retreading. [Solution] A non-pneumatic tire 100 comprising an inner cylinder 6 fitted onto a wheel 2, an outer cylinder 4 surrounding the inner cylinder 6 from the outside in the tire radial direction, a connecting member 3 connecting the inner cylinder 6 and the outer cylinder 4, and a tread member 5 provided on the outer side of the outer cylinder 4 in the tire radial direction, wherein the inner cylinder 6, the outer cylinder 4 and the connecting member 3 are made of a resin composition containing at least one selected from polyester thermoplastic resin and polyester thermoplastic elastomer, the tread member 5 includes two or more rubber layers 51, 52, the rubber layer 51 in contact with the outer cylinder 4 is not chlorinated, and the rubber component of the rubber layer 51 in contact with the outer cylinder 4 contains 50% by mass or more of isoprene skeleton rubber.

Description

Technical Field

[0001] The present invention relates to a non-pneumatic tire.

Background Art

[0002] In recent years, in order to avoid the occurrence of punctures, a non-pneumatic tire having a resinous skeleton member and a rubber tread member has been proposed as a tire that does not need to be filled with pressurized air inside (Patent Document 1 below). Also, even in such a non-pneumatic tire, from the viewpoint of recycling resources, there is an increasing need for so-called retreading, in which a worn rubber tread member is removed and a new tread member is attached.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-mentioned retreading, when removing a worn tread member, usually, a part of the tread member is left, and a new tread member (reclaimed rubber) is attached on the remaining tread member. However, as a result of the study by the present inventor, it has been found that when the retreading of the tread member is repeated, the adhesiveness between the remaining tread member and the resinous skeleton member decreases.

[0005] Therefore, an object of the present invention is to solve the problems of the above-mentioned conventional technology and provide a non-pneumatic tire capable of maintaining the adhesiveness between a resinous skeleton member and a rubber tread member even after retreading.

Means for Solving the Problems

[0006] The essential configuration of the non-pneumatic tire of the present invention, which solves the above problems, is as follows.

[0007] [1] 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, The inner cylinder, the outer cylinder, and the connecting member are made of a resin composition comprising at least one selected from polyester thermoplastic resins and polyester thermoplastic elastomers. The tread member comprises two or more rubber layers, the rubber layer in contact with the outer cylinder is not chlorinated, and the rubber component of the rubber layer in contact with the outer cylinder contains 50% by mass or more of isoprene skeleton rubber, characterized in that it is a non-pneumatic tire. The non-pneumatic tire of the present invention described in [1] above can maintain adhesion between the resin frame member and the rubber tread member even after retreading.

[0008] [2] The non-pneumatic tire according to [1], wherein the polyester thermoplastic resin and the polyester thermoplastic elastomer have a melting point of 150°C or higher. The non-pneumatic tires described in [2] above offer excellent shape stability in retreading.

[0009] [3] The non-pneumatic tire according to [1] or [2], wherein the tread member and the outer cylinder are bonded together with an adhesive. The non-pneumatic tire described in [3] above has significantly improved adhesion between the tread material and the outer cylinder.

[0010] [4] The non-pneumatic tire according to [3], wherein the adhesive is an epoxy adhesive or a phenolic adhesive. The non-pneumatic tire described in [4] above has improved adhesion between the tread material and the outer cylinder.

[0011] [5] The non-pneumatic tire according to [3], wherein the adhesive comprises a halogenated polymer. The non-pneumatic tire described in [5] above has improved adhesion between the tread material and the outer cylinder.

[0012] [6] A non-pneumatic tire according to any one of [3] to [5], wherein the adhesive used on the tread member side is different from the adhesive used on the outer cylinder side. The non-pneumatic tire described in [6] above can further improve the adhesion between the tread material and the outer cylinder.

[0013] [7] A non-pneumatic tire according to any one of [1] to [6], wherein the rubber component of the rubber layer in contact with the outer cylinder of the tread member contains 50% by mass or more of natural rubber. The non-pneumatic tires described in [7] above maintain adhesion between the outer cylinder and the tread material even after retreading, and are highly durable.

[0014] [8] The non-pneumatic tire according to any one of [1] to [7], wherein the rubber layer of the tread member in contact with the outer cylinder contains 20 parts by mass or more of carbon black per 100 parts by mass of the rubber component. The non-pneumatic tires described above [8] have high tread reinforcement properties.

[0015] [9] The non-pneumatic tire according to any one of [1] to [8], wherein the rubber layer of the tread member in contact with the outer cylinder contains less than 60 parts by mass of carbon black per 100 parts by mass of the rubber component. The non-pneumatic tires described above [9] have high grip performance because the modulus of elasticity of the tread material does not become too high.

[0016]

[10] The non-pneumatic tire according to [8] or [9], wherein the carbon black is recycled carbon black. The non-pneumatic tires described above

[10] have an increased proportion of sustainable materials and can contribute to the sustainability of society.

Advantages of the Invention

[0017] According to the present invention, it is possible to provide a non-pneumatic tire capable of maintaining the adhesiveness between a resinous skeleton member and a rubber tread member even when retreaded.

Brief Description of the Drawings

[0018] [Figure 1] It is an explanatory view seen from the side of the tire schematically showing the configuration of the non-pneumatic tire according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view taken along line II-II in FIG. 1.

Modes for Carrying Out the Invention

[0019] Hereinafter, the non-pneumatic tire of the present invention will be exemplified and described in detail based on its embodiments.

[0020] <Definition> The compounds described in this specification may be partially or wholly derived from fossil resources, may be derived from biological resources such as plant resources, or may be derived from recycled resources such as used tires. Further, it may be derived from a mixture of any two or more of fossil resources, biological resources, and recycled resources.

[0021] <Non-pneumatic tire> The non-pneumatic tire of this embodiment comprises an inner cylinder fitted onto 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 to connect the two cylinders, and a tread member provided on the outer side of the outer cylinder in the tire radial direction. In the non-pneumatic tire of this embodiment, the inner cylinder, the outer cylinder, and the connecting members are made of a resin composition containing at least one selected from polyester thermoplastic resin and polyester thermoplastic elastomer, the tread member includes two or more rubber layers, the rubber layer in contact with the outer cylinder is not chlorinated, and the rubber component of the rubber layer in contact with the outer cylinder contains 50% by mass or more of isoprene skeleton rubber.

[0022] The inner cylinder, outer cylinder, and connecting members (so-called skeletal members) of the non-pneumatic tire in this embodiment are made of a resin composition containing at least one selected from polyester-based thermoplastic resins and polyester-based thermoplastic elastomers, and have sufficient strength to support loads. Furthermore, the tread member of the non-pneumatic tire in this embodiment includes two or more rubber layers, and the rubber layer in contact with the outer cylinder is not treated with chlorine. If the rubber layer in contact with the outer cylinder of the tread member is treated with chlorine, there is a risk that the physical properties of the rubber layer in contact with the outer cylinder will deteriorate. However, in the non-pneumatic tire of this embodiment, since the rubber layer in contact with the outer cylinder of the tread member is not treated with chlorine, the deterioration of the physical properties of the rubber layer in contact with the outer cylinder can be suppressed. Furthermore, in the non-pneumatic tire of this embodiment, the rubber component of the rubber layer in contact with the outer cylinder of the tread member contains 50% by mass or more of isoprene skeleton rubber. Since rubber components with a proportion of isoprene skeleton rubber of 50% by mass or more experience little deterioration in physical properties, even if a portion of the tread member is left during retreading, the deterioration in the physical properties of the remaining tread member is minimal. And because the deterioration in the physical properties of the remaining tread member is minimal, the adhesion between the outer cylinder and the tread member is minimal even after retreading. Therefore, even after retreading, the non-pneumatic tire of this embodiment can maintain adhesion between the outer cylinder (resin skeletal member) and the tread member (rubber).

[0023] Next, the configuration of a non-pneumatic tire according to one embodiment of the present invention will be described. Figure 1 is a schematic diagram showing the configuration of a non-pneumatic tire according to one embodiment of the present invention, as viewed from the side of the tire, and Figure 2 is a cross-sectional view along the line II-II in Figure 1. Note that in Figures 1 and 2 used in the following explanation, the scale has been appropriately changed to make each component recognizable.

[0024] As shown in Figure 1, the non-pneumatic tire 100 of this embodiment comprises an inner cylinder 6 fitted onto a wheel 2, an outer cylinder 4 surrounding the inner cylinder 6 from the outside in the tire radial direction, a plurality of connecting members 3 arranged between the inner cylinder 6 and the outer cylinder 4 along the tire circumferential direction, connecting the two cylinders together (more specifically, connecting the outer circumferential surface of the inner cylinder 6 and the inner circumferential surface of the outer cylinder 4), and a tread member 5 provided on the outer side of the outer cylinder 4 in the tire radial direction.

[0025] As shown in Figure 1, the wheel 2, inner cylinder 6, outer cylinder 4, and tread member 5 are formed in an annular shape when viewed from the side. The central axes of the wheel 2, inner cylinder 6, outer cylinder 4, and tread member 5 are common and located coaxially. Hereinafter, the common central axis of the wheel 2, inner cylinder 6, outer cylinder 4, and tread member 5 will be referred to as the axis G, and the direction along the axis G will be referred to as the tire width direction (same as the axial direction; direction W in Figure 2). Also, when viewed from the axial direction, the direction that revolves around the axis G will be referred to as the tire circumferential direction (direction C in Figure 1), and the direction that intersects this axis G will be referred to as the tire radial direction (direction R in Figure 1). Furthermore, the front of the non-pneumatic tire 100 when viewed in the tire width direction may simply be referred to as the side of the tire 100.

[0026] The center points in the tire width direction of the wheel 2, inner cylinder 6, outer cylinder 4, and tread member 5 are all aligned with each other. In cross-sectional views along both the tire width direction and the tire diameter direction, the wheel 2, inner cylinder 6, outer cylinder 4, and tread member 5 as a whole exhibit a line-symmetrical shape with respect to a straight line passing through the center point (tire equator) in the tire width direction.

[0027] Wheel 2 is mounted on the axle of the vehicle. The outer surface of wheel 2 (the surface facing outward in the tire radial direction) is, for example, circular. Metal materials such as aluminum, aluminum alloy, and steel can be used for the wheel and axle. In addition, the wheel may be made of a resin composition containing at least one selected from polyester thermoplastic resin and polyester thermoplastic elastomer, similar to the inner cylinder 6, outer cylinder 4, and connecting member 3.

[0028] The inner cylinder 6 is formed in an annular shape. The inner cylinder 6 is fitted onto the outside of the wheel 2 and fixed (attached) to the wheel 2 so that the outer surface of the wheel 2 is inside the ring of the inner cylinder 6. The inner cylinder 6 is a connecting part for attaching the non-pneumatic tire 100 to the wheel 2 and is a base for supporting the non-pneumatic tire 100 on the wheel 2. The inner cylinder 6 is attached to the axle via the wheel 2. The central axes of the inner cylinder 6 and the outer cylinder 4 are arranged coaxially with the axis G. The inner cylinder 6, the connecting member 3 and the outer cylinder 4 are arranged so that their respective center portions in the tire width direction coincide with each other.

[0029] The outer cylinder 4 is formed in an annular shape, and the tread member 5 is attached to its outer circumferential surface. The outer cylinder 4 is formed to be elastically deformable at least toward the inside in the tire radial direction. The outer cylinder 4 is positioned to surround the inner cylinder 6 from the outside in the tire radial direction. The outer cylinder 4 is supported by the inner cylinder 6 by a connecting member 3, which will be described later.

[0030] The connecting member 3 is positioned between the outer circumferential surface of the inner cylinder 6 and the inner circumferential surface of the outer cylinder 4, and is a member that connects the outer circumferential surface of the inner cylinder 6 and the inner circumferential surface of the outer cylinder 4. The connecting member 3 is a plate-shaped member that extends radially from the outer circumferential surface of the inner cylinder 6 to the inner circumferential surface of the outer cylinder 4. The connecting member 3 as a whole is a curved plate shape, with its front and back surfaces facing in the circumferential or radial direction, and its side surfaces facing in the axial direction. The direction of extension of the connecting member 3 is slightly inclined in the circumferential direction. Multiple connecting members 3 are positioned between the outer circumferential surface of the inner cylinder 6 and the inner circumferential surface of the outer cylinder 4, and adjacent connecting members 3 are arranged at equal intervals in the circumferential direction. The connecting member 3 connects the outer circumferential surface of the inner cylinder 6 and the inner circumferential surface of the outer cylinder 4 so that they can be moved elastically relative to each other. The connecting member 3, as an example, comprises an outer base portion 31 that supports the outer cylinder 4, an inner base portion 32 that is supported by the inner cylinder 6, and an intermediate portion 33 that connects the outer base portion 31 and the inner base portion 32.

[0031] The outer base portion 31 extends inward in the tire radial direction and to one side in the tire circumferential direction from the inner circumferential surface of the outer cylinder 4. Both the front and back surfaces of the outer base portion 31 face the tire circumferential direction. That is, the outer base portion 31 extends inward from the inner circumferential surface of the outer cylinder 4 in the tire radial direction and is inclined to one side in the tire circumferential direction.

[0032] The intermediate portion 33 extends from the inner end of the outer base portion 31 in the tire radial direction toward the inside in the tire radial direction and toward one side in the tire circumferential direction. That is, the intermediate portion 33 extends from the inner end of the outer base portion 31 in the tire radial direction toward the inside in the tire radial direction, and is inclined toward one side in the tire circumferential direction. The connection portion between the outer base portion 31 and the intermediate portion 33 is curved so as to protrude toward the other side in the tire circumferential direction. That is, the intermediate portion 33 extends more inclined toward one side in the tire circumferential direction than the outer base portion 31.

[0033] The inner base portion 32 extends from the inner end of the intermediate portion 33 in the tire radial direction toward the inside in the tire radial direction and toward one side in the tire circumferential direction, and is connected to the outer circumferential surface of the inner cylinder 6. That is, the inner base portion 32 extends from the inner end of the intermediate portion 33 in the tire radial direction toward the inside in the tire radial direction, and is inclined toward one side in the tire circumferential direction. The connection portion between the intermediate portion 33 and the inner base portion 32 is curved so as to protrude toward one side in the tire circumferential direction. That is, the outer base portion 31 extends more inclined toward one side in the tire circumferential direction than the intermediate portion 33.

[0034] In the non-pneumatic tire 100 of this embodiment, the inner cylinder 6, outer cylinder 4, and connecting member 3, which serve as skeletal members, are made of a resin composition containing at least one selected from polyester-based thermoplastic resin and polyester-based thermoplastic elastomer. The inner cylinder 6, outer cylinder 4, and connecting member 3 may be formed integrally by, for example, injection molding, or they may be formed separately. Furthermore, the inner cylinder 6, outer cylinder 4, and connecting member 3 and the wheel 2 may be formed integrally, or they may be formed separately.

[0035] The resin composition comprises at least one selected from polyester thermoplastic resins and polyester thermoplastic elastomers, and may consist solely of the polyester thermoplastic resin and / or polyester thermoplastic elastomer, or may further contain various additives. The (total) content of polyester thermoplastic resin and / or polyester thermoplastic elastomer in the resin composition is preferably 80% by mass or more, and more preferably 90% by mass or more. Polyester thermoplastic resins and polyester thermoplastic elastomers have sufficient strength to support loads. Therefore, the inner cylinder 6, outer cylinder 4, and connecting member 3 made of a resin composition containing polyester thermoplastic resin and / or polyester thermoplastic elastomer have sufficient strength to support loads, and a non-pneumatic tire equipped with an inner cylinder 6, outer cylinder 4, and connecting member 3 made of a resin composition containing polyester thermoplastic resin and / or polyester thermoplastic elastomer offers an excellent balance of ride comfort and durability.

[0036] The polyester thermoplastic resin and / or polyester thermoplastic elastomer preferably have a melting point of 150°C or higher. When the melting point of the polyester thermoplastic resin and / or polyester thermoplastic elastomer is 150°C or higher, the shape of the inner cylinder 6, outer cylinder 4, and connecting member 3 can be sufficiently maintained by retreading at a temperature lower than 150°C. Therefore, a non-pneumatic tire having an inner cylinder 6, outer cylinder 4, and connecting member 3 made of a resin composition containing a polyester thermoplastic resin and / or polyester thermoplastic elastomer with a melting point of 150°C or higher exhibits excellent shape stability during retreading. The melting point of the polyester thermoplastic resin and / or polyester thermoplastic elastomer is more preferably 160°C or higher, even more preferably 170°C or higher, and preferably 250°C or lower, and even more preferably 230°C or lower. Here, the melting points of the polyester-based thermoplastic resin and the polyester-based thermoplastic elastomer are measured by differential scanning calorimetry (DSC) in accordance with JIS K7121.

[0037] Furthermore, the polyester-based thermoplastic resin and the polyester-based thermoplastic elastomer 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 polyester-based 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 polyester-based thermoplastic resins. Furthermore, "polyester thermoplastic elastomer" refers to a polyester thermoplastic resin material having hard segments and soft segments in its molecule. More specifically, it refers to a polyester thermoplastic resin material consisting of a copolymer of an elastic polymer compound, comprising a crystalline polymer with a high melting point that constitutes a hard segment, and an amorphous polymer with a low glass transition temperature that constitutes a soft segment. Note that the polyester thermoplastic elastomer in this invention does not include vulcanized rubber such as synthetic rubber.

[0038] The aforementioned polyester thermoplastic resin is a resin having ester bonds in its main chain. While the polyester thermoplastic resin is not particularly limited, crystalline polyester is preferred. Aromatic polyesters can be used as the crystalline polyester. Aromatic polyesters can, for example, be formed from 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, and polybutylene naphthalate, with polybutylene terephthalate being preferred.

[0039] 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.

[0040] Commercially available polyester thermoplastic 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 "Trecon" series from Toray Industries, Inc. (e.g., 1401X06, 1401X31, 1401X70, etc.), and the "Planac" series from Toyobo Co., Ltd. (e.g., BT-1000).

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.).

[0045] The resin composition may contain other resin components and additives in addition to the polyester thermoplastic resin and / or polyester thermoplastic elastomer described above. Examples of resin components other than polyester thermoplastic resins and polyester thermoplastic elastomers include polyolefin thermoplastic resins, polystyrene thermoplastic resins, polyolefin thermoplastic elastomers (TPO), and polystyrene thermoplastic elastomers (TPS). Examples of additives added to the resin composition include weather-resistant anti-aging agents, heat-resistant anti-aging agents, moisture-resistant heat additives, antistatic agents, lubricants, 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 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.

[0046] The polyolefin-based thermoplastic resin has a main chain of olefin polymers such as ethylene, propylene, and 1-butene. Examples of the polyolefin-based thermoplastic 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.

[0047] As the aforementioned polyolefin-based thermoplastic 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.

[0048] The aforementioned polyolefin-based thermoplastic resin is preferably modified, that is, preferably a modified polyolefin resin. Examples of modified polyolefin resins include maleic anhydride-modified polyolefin resin, acrylic acid-modified polyolefin resin, methacrylic acid-modified polyolefin resin, and the like. As the modified polyolefin resin, commercially available products can be used. For example, Sanyo Chemical Industries' "Yumex" series can be used as a maleic acid-modified polypropylene resin, Kuraray's "CB Polymer" series as a carboxylic acid-modified polypropylene resin, and Mitsui Chemicals' "Admer" series as a maleic anhydride-modified polypropylene resin.

[0049] The polystyrene-based thermoplastic resin is a polymer containing styrene as a monomer unit. Examples of the polystyrene-based thermoplastic resin include polystyrene resin and acrylonitrile-butadiene-styrene copolymer resin (ABS resin). As the aforementioned polystyrene resin, commercially available products can be used, such as Zarec (registered trademark) manufactured by Idemitsu Kosan Co., Ltd., Toyo Styrene Co., Ltd., Toyo Styrofoam (registered trademark) manufactured by Toyo Styrene Co., Ltd., and Sebian manufactured by Daicel Polymer Co., Ltd. The aforementioned acrylonitrile-butadiene-styrene copolymer resin (ABS resin) is a terpolymer of acrylonitrile, butadiene, and styrene. Commercially available ABS resins can be used, such as Toyorac® manufactured by Toray Industries, Inc.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.).

[0054] 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.

[0055] 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 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 of the resin composition.

[0056] The aforementioned heat-resistant anti-aging agent is an additive that has the effect of improving the heat resistance of the resin composition, and a phenolic compound (hindered phenolic compound) is preferred as the heat-resistant anti-aging agent. 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 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 of the resin composition.

[0057] The aforementioned moisture-resistant heat additive is an additive that improves the moisture-resistant heat properties of the resin composition. 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 amount of moisture-resistant heat additive added is preferably in the range of 1 to 15 parts by mass per 100 parts by mass of the resin component of the resin composition.

[0058] The method for preparing the resin composition is not particularly limited. The resin components may be mixed first and then the additive may be added. Alternatively, the resin components and the additive may be mixed at the same time. Furthermore, multiple resin components to which the additive has been added beforehand may be mixed. Finally, resin components to which the additive has been added may be mixed with resin components to which the additive has not been added.

[0059] The tread member 5 is formed in a cylindrical shape that extends in the width direction with respect to the axis G. The tread member 5 is fitted and fixed (attached) to the outside of the outer cylinder 4. The tread member 5 may cover not only the outer circumferential surface of the outer cylinder 4, but also the outer end in the tire diameter direction of the side surface facing the width direction.

[0060] The tread member 5 includes two rubber layers 51 and 52. Each rubber layer 51 and 52 is laminated in the tire radial direction to form the tread member 5. Rubber layer 51 is located on the innermost side of the tread member 5 in the tire radial direction and is in contact with the outer cylinder 4. On the other hand, rubber layer 52 is not in contact with the outer cylinder 4 and is located on the outer side of rubber layer 51 in the tire radial direction. Although the tread member 5 of the non-pneumatic tire 100 shown in Figure 1 consists of two rubber layers 51 and 52, the tread member of the non-pneumatic tire of the present invention may consist of two rubber layers or may include three or more rubber layers.

[0061] The rubber layer 51 of the tread member 5 that is in contact with the outer cylinder 4 is not treated with chlorine. By not treating the rubber layer 51 of the tread member 5 that is in contact with the outer cylinder 4 with chlorine, the deterioration of the physical properties of the rubber layer 51 in contact with the outer cylinder 4 can be suppressed.

[0062] In the non-pneumatic tire 100 of this embodiment, it is preferable that the tread member 5 and the outer cylinder 4 are bonded together with an adhesive. In the non-pneumatic tire 100 of this embodiment, in order to suppress the deterioration of the physical properties of the rubber layer 51 that is in contact with the outer cylinder 4, the rubber layer 51 in contact with the outer cylinder 4 is not subjected to chlorine treatment. However, by bonding the tread member 5 and the outer cylinder 4 together with an adhesive, the adhesion between the tread member 5 and the outer cylinder 4 can be sufficiently improved even without chlorine treatment being applied to the rubber layer 51 in contact with the outer cylinder 4. Therefore, in a non-pneumatic tire in which the tread member 5 and the outer cylinder 4 are bonded together with an adhesive, the adhesion between the tread member 5 and the outer cylinder 4 is sufficiently improved.

[0063] The adhesive is preferably an epoxy adhesive or a phenolic adhesive. Epoxy adhesives and phenolic adhesives have excellent adhesion between rubber and resin, and are highly effective in improving the adhesion between the rubber tread member 5 and the resin outer cylinder 4. Therefore, in a non-pneumatic tire in which the tread member 5 and the outer cylinder 4 are bonded with an epoxy adhesive or a phenolic adhesive, the adhesion between the tread member 5 and the outer cylinder 4 is further improved.

[0064] The epoxy adhesives mentioned above are adhesives containing epoxy compounds or epoxy resins, and examples of such epoxy adhesives include "EP138," "EP160," and "EP170" manufactured by Cemedyne Co., Ltd. The phenolic adhesives mentioned above are adhesives containing phenol compounds or phenolic resins, and examples of such phenolic adhesives include "Metalock UB," "Metalock U-20," "Metalock PH-56," and "Metalock N-20" manufactured by Toyo Chemical Research Institute Co., Ltd. These adhesives may contain both epoxy compounds and / or epoxy resins, and adhesives containing both are sometimes referred to as "epoxy-phenolic adhesives."

[0065] The adhesive may also preferably contain a halogenated polymer. Adhesives containing halogenated polymers have excellent adhesive strength between rubber and resin, and are highly effective in improving the adhesion between the rubber tread member 5 and the resin outer cylinder 4. Therefore, in a non-pneumatic tire in which the tread member 5 and the outer cylinder 4 are bonded with an adhesive containing a halogenated polymer, the adhesion between the tread member 5 and the outer cylinder 4 is further improved.

[0066] Examples of halogenated polymers include chlorinated natural rubber, chlorinated polyethylene, chlorosulfonated polyethylene, and chlorinated polybutadiene. Adhesives containing the halogenated polymer can be prepared by dissolving the halogenated polymer in a solvent. Examples of solvents include xylene, ethylbenzene, and propylene glycol monomethyl ether. Examples of adhesives containing the halogenated polymer include "CHEMLOK 6108" from Rhode & Co., Ltd., and "METALOK F-112" and "METALOK G-165" from Toyo Chemical Research Institute Co., Ltd.

[0067] In the non-pneumatic tire 100 of this embodiment, it is preferable that the adhesive used on the tread member 5 side is different from the adhesive used on the outer cylinder 4 side. When the adhesive used on the tread member 5 side is different from the adhesive used on the outer cylinder 4 side, the adhesion between the tread member 5 and the outer cylinder 4 can be further improved by appropriately combining adhesive properties that are excellent for bonding with the rubber tread member 5 and adhesive properties that are excellent for bonding with the resin outer cylinder 4. Here, as the adhesive used on the tread member 5 side, an adhesive containing the halogenated polymer is preferred, and as the adhesive used on the outer cylinder 4 side, the epoxy adhesive and the phenolic adhesive are preferred.

[0068] In the non-pneumatic tire 100 of this embodiment, the rubber layer 51 of the tread member 5 that is in contact with the outer cylinder 4 contains rubber components and may contain other components as needed. The rubber layer 51 in contact with the outer cylinder 4 can be formed from a rubber composition in which various compounding agents are blended with the rubber components. The content of rubber components in the entire rubber layer 51 that is in contact with the outer cylinder 4 (i.e., the content of rubber components in the entire rubber composition used for the rubber layer 51 that is in contact with the outer cylinder 4) is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. Furthermore, the content of rubber components in the entire rubber layer 51 that is in contact with the outer cylinder 4 may be 95% by mass or less, 85% by mass or less, or 75% by mass or less.

[0069] The rubber component of the rubber layer 51 in contact with the outer cylinder 4 contains 50% by mass or more of isoprene skeleton rubber, and may also contain other rubber components. Rubber components with an isoprene skeleton rubber content of 50% by mass or more exhibit little deterioration in physical properties, so even if a portion of the tread member is left in retreading, the deterioration in the physical properties of the remaining tread member is minimal. The proportion of isoprene skeleton rubber in the rubber component of the rubber layer 51 in contact with the outer cylinder 4 is preferably 70% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass. Other rubber components besides isoprene-backed rubber include butadiene rubber (BR), styrene-butadiene rubber (SBR), and chloroprene rubber (CR).

[0070] The rubber component of the rubber layer 51 of the tread member 5 that is in contact with the outer cylinder 4 preferably contains 50% by mass or more of natural rubber. Because natural rubber has excellent physical properties, even if a part of the tread member is left after retreading, the physical properties of the remaining tread member are excellent. Therefore, a non-pneumatic tire in which the rubber component of the rubber layer 51 in contact with the outer cylinder 4 contains 50% by mass or more of natural rubber can maintain adhesion between the outer cylinder 4 and the tread member 5 even after retreading, and also has excellent durability. The proportion of natural rubber in the rubber component of the rubber layer 51 in contact with the outer cylinder 4 is more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass.

[0071] The rubber layer 51 of the tread member 5 that is in contact with the outer cylinder 4 (the rubber composition used for the rubber layer 51 in contact with the outer cylinder 4) may contain, in addition to the rubber components described above, reinforcing fillers such as carbon black, vulcanizing agents, vulcanization accelerators, fatty acids or their salts, metal oxides, process oils, antioxidants, etc. As the vulcanizing agent, known vulcanizing agents such as sulfur, organic peroxides, and resin vulcanizing agents can be used. Among these, sulfur is preferably used as the vulcanizing agent. Known vulcanization accelerators, such as aldehydes, ammonias, amines, guanidines, thioureas, thiazoles, sulfenamides, thiurams, dithiocarbamates, and xanthetes, can be used. Examples of fatty acids include stearic acid, palmitic acid, myristic acid, and lauric acid, and these may also be incorporated in salt form, such as zinc stearate. Among these, stearic acid is preferred. Examples of metal oxides include zinc oxide (zinc oxide), iron oxide, and magnesium oxide, with zinc oxide being preferred among them. For the process oil, any type of oil may be used: aromatic, naphthenic, or paraffinic. Anti-aging agents include amine-ketone, imidazole, amine, phenol, sulfur, and phosphorus-based agents.

[0072] When the rubber layer 51 in contact with the outer cylinder 4 of the tread member 5 contains carbon black, it is preferable that the rubber layer 51 contains 20 parts by mass or more of carbon black per 100 parts by mass of the rubber component. A non-pneumatic tire in which the rubber layer 51 in contact with the outer cylinder 4 of the tread member 5 contains 20 parts by mass or more of carbon black per 100 parts by mass of the rubber component has high reinforcing properties for the tread member 5. Furthermore, if the rubber layer 51 in contact with the outer cylinder 4 of the tread member 5 contains carbon black, it is preferable that the rubber layer 51 contains less than 60 parts by mass of carbon black per 100 parts by mass of the rubber component. A non-pneumatic tire in which the rubber layer 51 in contact with the outer cylinder 4 of the tread member 5 contains less than 60 parts by mass of carbon black per 100 parts by mass of the rubber component does not have an excessively high modulus of elasticity of the tread member 5, resulting in high grip performance.

[0073] Preferably, the carbon black is recycled carbon black. Since recycled carbon black is a material derived from recycled resources, a non-pneumatic tire in which the rubber layer 51 in contact with the outer cylinder 4 of the tread member 5 contains recycled carbon black has an improved proportion of sustainable materials and can contribute to the sustainability of society.

[0074] In this specification, "recycled carbon black" refers to carbon black obtained by recovering from raw materials that are waste materials submitted for recycling. Examples of such waste materials include waste rubber, used tires, and waste oil. Waste rubber refers to all discarded rubber, including not only rubber generated from rubber products but also unwanted scraps generated during the production or repair of rubber products. Examples of scraps include buffing powder and peeling rubber. Buffing powder is fine rubber generated, for example, in the buffing process of retreading tires, where the tread portion remaining on the base tire is scraped off. Peeling rubber is long pieces of rubber, for example, 1 to 2 cm wide, that are peeled off from the surface of rubber products such as tires. Peeling rubber is generated by scraping the surface of rubber products such as tires using a U-shaped or V-shaped knife like a peeler. Furthermore, waste rubber includes not only cross-linked rubber but also unvulcanized rubber. Rubber products include, for example, final products such as tires and rubber hoses, and rubber parts or components at the manufacturing stage of final products. Used tires may include, for example, tires that have been retreaded, tires generated from tire replacement or vehicle scrapping, and End-of-Life Tires (ELTs) that have reached the end of their lifespan, or any other type of tire that has been discarded for any reason. Waste oil is not limited to that generated when plastics and rubber are broken down, but also includes used oils discharged from industry, such as animal and vegetable oils, lubricating oils, insulating oils, and cutting oils. Among these, waste oil that does not contain any non-organic components, such as those derived from silicone rubber or polyvinyl chloride, is preferable. Furthermore, waste oil that contains carbon black or rubber containing carbon black is preferable. "Recycled carbon black" is different from carbon black that is not recycled, which is manufactured directly using hydrocarbons such as petroleum, natural gas, and coal as raw materials. Furthermore, "used" here includes not only carbon black that has been discarded after actual use, but also carbon black that was manufactured but discarded without actually being used.

[0075] Furthermore, it is preferable that the recycled carbon black is obtained by thermal decomposition of a vulcanized rubber product containing carbon black. Recycled carbon black obtained by thermal decomposition of a vulcanized rubber product containing carbon black is readily available because a large amount of vulcanized rubber products containing carbon black exist and it can be easily obtained by thermal decomposition. Moreover, it is preferable that the recycled carbon black is obtained from the solid residue generated by the thermal decomposition of the vulcanized rubber product containing carbon black. When a rubber product containing carbon black is thermally decomposed, solid residue and volatile components (oil) are obtained, and recycled carbon black can be recovered from either. Furthermore, when recovering carbon black from volatile components, it is possible to recover oil with a specific gravity suitable for carbon black production and use it to produce carbon black using existing carbon black production methods (for example, Japanese Patent Publication No. 2015-520259). In this case, unlike carbon black recovered from solid residues, there are advantages such as the absence of impurities and the absence of mixtures of different grades. In addition, in the production of low-environmental-impact carbon black, there are various options other than using oil obtained by recovering volatile components from the aforementioned rubber pyrolysis, such as using vegetable oil or oil derived from waste plastics. However, edible resources such as vegetable oil present challenges in securing sufficient quantities due to other uses such as food, and the environmental impact associated with the expansion of cultivated land must also be considered. Similarly, oil derived from waste plastics is also used for other purposes such as horizontal recycling of plastics, so supply issues are also likely to arise. On the other hand, when using vulcanized rubber products, particularly volatile components (oils) produced by the thermal decomposition of tires, the tire industry has a system in place to continue using existing materials. This allows for the continued use of existing materials, reducing the consumption of new materials in new tire manufacturing and contributing to a reduction in the industry's environmental impact. The grades of carbon black mentioned above are not particularly limited, but include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc.

[0076] The solid residue obtained by thermally decomposing waste materials such as used rubber and used tires contains ash in addition to carbon black. The ash originates from non-volatile components contained in rubber and tires. Therefore, the recycled carbon black obtained from this solid residue has a relatively low carbon black content. On the other hand, considering the various physical properties required for tires manufactured using recycled carbon black, a higher carbon content in recycled carbon black is preferable. In the recycled carbon black, the carbon content is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 87% by mass or more, and particularly preferably 89% by mass or more. Furthermore, the carbon content in the recycled carbon black is preferably 97% by mass or less. Note that the carbon content does not include adsorbed water.

[0077] The aforementioned ash content specifically includes zinc oxide, zinc sulfide, silica, iron compounds (iron oxide), calcium oxide, aluminum oxide, magnesium oxide, and the like. In the case of recycled carbon black produced from solid residue obtained by thermal decomposition of waste, a certain amount of ash remains even after various processes to remove it. In this embodiment, the presence of ash in recycled carbon black is permitted. In one embodiment, the lower limit of the ash content of the recycled carbon black may be 0.5% by mass.

[0078] Furthermore, the recycled carbon black can be obtained from the pyrolysis process of used pneumatic tires. For example, European Patent Application Publication No. 3427975, referring to "Rubber Chemistry and Technology," Vol. 85, No. 3, pp. 408-449 (2012), particularly pp. 438, 440, and 442, states that it can be obtained by the pyrolysis of organic materials at 550-800°C in the absence of oxygen, or by vacuum pyrolysis at relatively low temperatures (paragraph

[0027] ). Carbon black obtained from such pyrolysis processes usually lacks functional groups on its surface, as referred to in paragraph

[0004] of Japanese Patent Publication No. 6856781 (Comparison of Surface Morphology and Chemistry of Pyrolysis Carbon Black and Commercial Carbon Black, Powder Technology 160 (2005) 190-193).

[0079] The recycled carbon black may lack functional groups on its surface, or it may have been treated to include functional groups on its surface. Treatment to include functional groups on the surface of recycled carbon black can be carried out by conventional methods. For example, in European Patent Application Publication No. 3173251, carbon black obtained from a thermal decomposition process is treated with potassium permanganate under acidic conditions to obtain carbon black containing hydroxyl groups and / or carboxyl groups on its surface. In addition, in Japanese Patent Publication No. 6856781, carbon black obtained from a thermal decomposition process is treated with an amino acid compound containing at least one thiol group or disulfide group to obtain carbon black with an activated surface. The recycled carbon black according to this embodiment also includes carbon black that has been treated to include functional groups on its surface.

[0080] Furthermore, for the thermal decomposition of cross-linked rubber products (vulcanized rubber products) such as used tires, one example is a thermal decomposition method at a temperature of 650°C or higher.

[0081] The cross-linked rubber products used in the aforementioned decomposition may be grouped by the type of rubber component they contain beforehand, and the decomposition process may be carried out for each group separately. Alternatively, they may be grouped by the type of filler they contain beforehand (for example, the type of carbon black, the type of silica, the mixing ratio of carbon black and silica, etc.), and the decomposition process may be carried out for each group separately. Furthermore, they may be grouped by both the type of rubber component and the type of filler, and the decomposition process may be carried out for each group separately. When the decomposition process is carried out for each group in this way, recycled carbon black with more uniform physical properties can be obtained, and when it is again incorporated into the rubber component, a rubber composition with better performance can be obtained.

[0082] Furthermore, if the cross-linked rubber product used in the decomposition is derived from a tire, it may be grouped in advance by tire type (for example, for passenger cars, trucks and buses, heavy vehicles such as off-road vehicles, aircraft, agricultural vehicles, etc.) and then the decomposition process may be carried out for each group. Alternatively, it may be grouped in advance by tire component (for example, tread rubber, sidewall rubber, bead rubber, steel cord coated rubber, organic fiber coated rubber, pad rubber, cushion rubber, etc.) and then the decomposition process may be carried out for each group. In addition, it may be possible to group by tire type and by tire component and then carry out the decomposition process for each group. When the decomposition process is carried out for each group in this way, recycled carbon black with more uniform physical properties can be obtained, and when it is again blended into the rubber component, a rubber composition with better performance can be obtained.

[0083] The aforementioned recycled carbon black has a nitrogen adsorption specific surface area of ​​40-100 m² as determined by the BET method. 2 It is preferable that the amount be / g, and 50-90m 2 It is more preferable that the amount be / g, which is 55-75m 2 It is particularly preferable that the value be / g. Herein, in this specification, the nitrogen adsorption specific surface area of ​​recycled carbon black by the BET method is the statistical thickness specific surface area (STSA), which is determined according to ASTM D6556.

[0084] The recycled carbon black preferably has a pH of 4 to 12, more preferably 5 to 11, and particularly preferably 6 to 10. Herein, in this specification, the pH of recycled carbon black is determined according to ASTM D1512.

[0085] The recycled carbon black preferably has a toluene color transmission rate of 60% or more, more preferably 70% or more, and particularly preferably 80% or more. Herein, in this specification, the toluene staining transmittance of recycled carbon black is determined according to ASTM D1618.

[0086] The recycled carbon black preferably has a heating loss of 3% by mass or less at 125°C, more preferably 2.5% by mass or less, and particularly preferably 2% by mass or less. Herein, in this specification, the heating loss of recycled carbon black at 125°C is determined according to ASTM D1509.

[0087] The recycled carbon black preferably has a sulfur content of 5% by mass or less, more preferably 3.5% by mass or less, and particularly preferably 3% by mass or less.

[0088] The recycled carbon black preferably has a residue of 20 ppm by mass or less after sieving with a 35 mesh, more preferably 15 ppm by mass or less, and particularly preferably 10 ppm by mass or less. Herein, in this specification, the 35-mesh sieve residue of recycled carbon black is determined according to ASTM D1514.

[0089] The recycled carbon black preferably has a residue of 1,000 ppm by mass or less after sieving with a 325 mesh (44 μm), more preferably 700 ppm by mass or less, and particularly preferably 300 ppm by mass or less. Herein, in this specification, the 325-mesh (44 μm) sieve residue of recycled carbon black is determined according to ASTM D1514.

[0090] The recycled carbon black preferably has a pellet hardness of 100 cN or less, more preferably 90 cN or less, and particularly preferably 80 cN or less. Herein, in this specification, the pellet hardness of recycled carbon black is determined according to ASTM D5230.

[0091] The recycled carbon black preferably has a pelletized fine powder content of 10% by mass or less, more preferably 7% by mass or less, and particularly preferably 5% by mass or less. Herein, in this specification, the amount of recycled carbon black pellets is determined according to ASTM D1508.

[0092] The recycled carbon black preferably has a particle size (D97) of 25 μm or less, more preferably 15 μm or less, and particularly preferably 10 μm or less. In this specification, the particle size (D97) of recycled carbon black is determined using a laser diffraction particle size analyzer, with a refractive index of 1.33 for water and 1.75 for the filler.

[0093] The recycled carbon black preferably contains 50% or more by volume of particles 5 μm or smaller, more preferably 70% or more by volume, and particularly preferably 80% or more by volume.

[0094] The recycled carbon black preferably has an ash content of 25% by mass or less, more preferably 20% by mass or less, and particularly preferably 15% by mass or less. When the ash content of the recycled carbon black is 25% by mass or less, the various physical properties of rubber products to which the rubber composition is applied can be improved. Herein, in this specification, the ash content of recycled carbon black is determined according to ASTM D8474·D1506.

[0095] The recycled carbon black preferably has a dibutyl phthalate (DBP) absorption rate of 70 to 120 mL / 100 g, more preferably 75 to 110 mL / 100 g, and particularly preferably 80 to 100 mL / 100 g. Herein, in this specification, the DBP absorption amount of recycled carbon black is determined according to ASTM D2414.

[0096] The recycled carbon black preferably has a compressed dibutyl phthalate (24M4DBP) absorption capacity of 50 to 110 mL / 100 g, more preferably 60 to 100 mL / 100 g, and particularly preferably 70 to 90 mL / 100 g. Herein, in this specification, the 24M4DBP absorption amount of recycled carbon black is determined according to ASTM D3493.

[0097] Commercially available recycled carbon black can be used. Examples of such commercially available products include "PB365" manufactured by Enrestec. PB365 is recycled carbon black produced by the thermal decomposition of used tires, and has a nitrogen adsorption specific surface area of ​​73.6 m² according to the BET method. 2 It is [value] / g and also contains approximately 17% by mass of ash.

[0098] The rubber layer 52 of the tread member 5 that does not come into contact with the outer cylinder 4 (the rubber composition used for the rubber layer 52 that does not come into contact with the outer cylinder 4) is not particularly limited, and may, for example, in addition to rubber components, contain reinforcing fillers such as carbon black, vulcanizing agents, vulcanization accelerators, fatty acids or their salts, metal oxides, process oils, antioxidants, etc. These rubber components and various compounding agents can be the same as those used for the rubber layer 51 that comes into contact with the outer cylinder 4, or different ones may be used depending on the purpose (performance on the road surface, etc.).

[0099] Although a non-pneumatic tire according to one embodiment of the present invention has been described above, various modifications can be made to the non-pneumatic tire of the present invention. [Examples]

[0100] 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.

[0101] (Examples 1 and 2) (1) Fabrication of skeletal members A resin skeletal member consisting of an inner cylinder, outer cylinder, and connecting members, as shown in Figures 1 and 2, is fabricated by injection molding P-90B (manufactured by Toyobo MC Co., Ltd., product name "Perprene P-type P-90B", melting point = 203℃) at 265℃. Next, a phenolic adhesive (manufactured by Toyo Chemical Research Institute, product name "Metalock N-20", phenolic resin content = 10-20% by mass, epoxy resin content = 0-10% by mass, synthetic rubber content = 0-10% by mass, methanol content = 0-10% by mass, 2-propanol content = 0-1% by mass, methyl isobutyl ketone content = 20-30% by mass, propylene glycol monomethyl ether content = 10-20% by mass, ethyl methyl ketone content = 30-40% by mass, phenol After applying a mixture containing 0-1% by mass of xylene, cresol, formaldehyde, and other additives, then apply a vulcanizing adhesive (manufactured by Toyo Chemical Research Institute, product name "Metalock G-165", containing 37% by mass of xylene, 36% by mass of ethylbenzene, 0.4% by mass of toluene, 3.4% by mass of propylene glycol monomethyl ether, 1.7% by mass of carbon black, and 21% by mass of halogenated polymers and other additives).

[0102] (2) Fabrication of tread members A rubber composition with the formulation shown in Table 1 is prepared, and an unvulcanized rubber sheet with a thickness of 1.0 mm is made from this rubber composition. Additionally, tread rubber (vulcanized rubber) will need to be prepared separately.

[0103] (3) Manufacturing of non-pneumatic tires The unvulcanized rubber sheet is laminated onto the outer surface of the skeletal member (the outer surface of the outer cylinder) such that the adhesive-coated surface of the outer cylinder of the skeletal member is in contact with the unvulcanized rubber sheet. Furthermore, a separately prepared tread rubber (vulcanized rubber) is laminated on top of the unvulcanized rubber sheet, and the autoclave is placed in the autoclave and held for 90 minutes under conditions of a temperature of 120°C and a pressure of 1.3 MPa to bond the tread member (a laminate of unvulcanized rubber sheet and tread rubber (vulcanized rubber)) to the skeletal member, thereby producing a non-pneumatic tire with the structure shown in Figures 1 and 2.

[0104] (4) Retread The tread material is peeled off from the manufactured non-pneumatic tire to create a base tire (with some parts remaining that originate from the unvulcanized rubber sheet). A 1.0 mm thick unvulcanized rubber sheet, made from the rubber composition shown in Table 1, is placed on top of the base tire. A separately prepared retreaded rubber (vulcanized rubber) is then placed on top of the unvulcanized rubber sheet, and the autoclave is placed under conditions of 120°C and 1.3 MPa pressure for 90 minutes to bond the retreaded rubber and the base tire, thereby creating a non-pneumatic tire that has undergone one retreading process. Furthermore, the above procedure for retreading is repeated twice on a separately prepared non-pneumatic tire to create a non-pneumatic tire that has been retreaded twice.

[0105] (5) Method for evaluating adhesion A retreaded, non-pneumatic tire is mounted on a jig that rotates around its center axis. The edge of the tread material (reconditioned rubber) is grasped, and it is peeled from the skeletal material in a 90° peeling manner. The peeling speed is set to 100 mm / min. At this time, the proportion of the peeled area in which the tread material (reconditioned rubber) is damaged by the base material is measured, and the adhesion is evaluated according to the following criteria. Excellent: Over 90% of the base material is destroyed. Good: The percentage of base material failure is between 50% and 90%. Defective: Less than 50% of the base material is damaged.

[0106] (Comparative Example 1) (1) Fabrication of skeletal members A resin skeletal member consisting of an inner cylinder, an outer cylinder, and connecting members, as shown in Figures 1 and 2, is fabricated in the same manner as in Examples 1 and 2.

[0107] (2) Fabrication of tread members A rubber composition with the formulation shown in Table 1 is prepared, molded into a predetermined shape, and then vulcanized at 160°C for 10 minutes to produce a rubber tread member. Chemlok 7701 (manufactured by Road Japan Inc.) is applied to the surface of the tread member that will be in contact with the outer cylinder (the surface that will be the inner circumferential surface) and subjected to chlorination treatment.

[0108] (3) Manufacturing of non-pneumatic tires The tread member is wrapped around the outer surface of the skeletal member (the surface of the outer cylinder) so that the chlorinated surface of the tread member is in contact with the outer surface of the skeletal member (the surface of the outer cylinder). The tread member is then placed in an autoclave and held at a temperature of 120°C and a pressure of 1.3 MPa for 90 minutes to bond the tread member and the skeletal member, thereby producing a non-pneumatic tire with the structure shown in Figures 1 and 2. The non-pneumatic tires prepared were retreaded in the same manner as in Examples 1 and 2, and their adhesion was evaluated.

[0109] [Table 1]

[0110] *1 Natural rubber *2 Butadiene rubber: Manufactured by ENEOS Material Co., Ltd., product name "BR01" *3 Carbon Black 1: Manufactured by Columbia Carbon, product name "Statex n550" *4 Carbon Black 2: Manufactured by Tokai Carbon Co., Ltd., product name "Seast 300" *5 Others: Total amount of sulfur, vulcanization accelerator, zinc oxide, oil, etc.

[0111] Table 1 shows that the non-pneumatic tires of Examples 1 and 2 maintain adhesion between the resin skeletal member (outer cylinder) and the rubber tread member even after repeated retreading. On the other hand, in Comparative Example 1, a non-pneumatic tire in which the rubber layer in contact with the outer cylinder of the tread member is treated with chlorine, it can be seen that repeated retreading significantly reduces the adhesion between the resin skeletal member (outer cylinder) and the rubber tread member.

[0112] [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: Climate Action," among others. [Explanation of Symbols]

[0113] 100: Non-pneumatic tires 2: Wheels 3: Connecting member 31: External base 32: Inner base 33: Middle section 4: Outer cylinder 5: Tread material 51, 52: Rubber layer 6: Inner cylinder G: Axial center C: Tire circumferential direction R: Tire radial direction W: Tire width direction

Claims

1. 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 inner cylinder, the outer cylinder, and the connecting member are made of a resin composition comprising at least one selected from polyester thermoplastic resins and polyester thermoplastic elastomers. The tread member comprises two or more rubber layers, the rubber layer in contact with the outer cylinder is not chlorinated, and the rubber component of the rubber layer in contact with the outer cylinder contains 50% by mass or more of isoprene skeleton rubber, characterized in that it is a non-pneumatic tire.

2. The non-pneumatic tire according to claim 1, wherein the polyester thermoplastic resin and the polyester thermoplastic elastomer have a melting point of 150°C or higher.

3. The non-pneumatic tire according to claim 1, wherein the tread member and the outer cylinder are bonded together with an adhesive.

4. The non-pneumatic tire according to claim 3, wherein the adhesive is an epoxy adhesive or a phenolic adhesive.

5. The non-pneumatic tire according to claim 3, wherein the adhesive comprises a halogenated polymer.

6. A non-pneumatic tire according to any one of claims 3 to 5, wherein the adhesive used on the tread member side is different from the adhesive used on the outer cylinder side.

7. The non-pneumatic tire according to claim 1, wherein the rubber component of the rubber layer in contact with the outer cylinder of the tread member contains 50% by mass or more of natural rubber.

8. The non-pneumatic tire according to claim 1, wherein the rubber layer of the tread member in contact with the outer cylinder contains 20 parts by mass or more of carbon black per 100 parts by mass of the rubber component.

9. The non-pneumatic tire according to claim 1, wherein the rubber layer of the tread member in contact with the outer cylinder contains less than 60 parts by mass of carbon black per 100 parts by mass of the rubber component.

10. The non-pneumatic tire according to claim 8 or 9, wherein the carbon black is recycled carbon black.

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