Non-pneumatic tire and thermosetting resin composition

Abstract

To provide a non-pneumatic tire which can inhibit change of rupture stress of a support structure and inhibit discoloration of the support structure even if the non-pneumatic tire is used for a long time.SOLUTION: A non-pneumatic tire 1 includes: a support structure 10; and a tread 50 which is located at the outer side relative to the support structure 10 in a tire radial direction X and extends along a tire circumferential direction C. The support structure 10 contains resins and additive agents. The additive agents contain a phenolic antioxidant and a hindered amine light stabilizer. The hindered amine light stabilizer has amino-ether groups.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a non-pneumatic tire and a thermosetting resin composition.

Background Art

[0002] Conventionally, a non-pneumatic tire is known that includes a support structure that supports a load from a vehicle, and a tread that is located radially outside the support structure and extends along the tire circumferential direction.

[0003] Patent Document 1 describes a support structure that contains a resin and an additive and has an oxidation induction time of 4 minutes or more. Here, the additive is at least one selected from the group consisting of an ultraviolet blocker, an ultraviolet absorber, an antioxidant, and a light stabilizer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Here, even when the non-pneumatic tire is used for a long period of time, it is desired to suppress a change in the breaking stress of the support structure and suppress discoloration of the support structure.

[0006] An object of the present invention is to provide a non-pneumatic tire capable of suppressing a change in the breaking stress of the support structure and suppressing discoloration of the support structure even when used for a long period of time.

Means for Solving the Problems

[0007] One aspect of the present invention is a non-pneumatic tire, comprising a support structure and a tread located radially outside the support structure in the tire diameter direction and extending along the tire circumferential direction, wherein the support structure contains a resin and an additive, the additive contains a phenolic antioxidant and a hindered amine light stabilizer, and the hindered amine light stabilizer has an amino ether group.

[0008] Another aspect of the present invention is a thermosetting resin composition used for manufacturing the support structure of a non-pneumatic tire, which contains a resin precursor and an additive, the additive contains a phenolic antioxidant and a hindered amine light stabilizer, and the hindered amine light stabilizer has an amino ether group.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a non-pneumatic tire that can suppress changes in the breaking stress of the support structure and suppress discoloration of the support structure even after long-term use.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] Figure 1 shows the non-pneumatic tire of the present embodiment. The non-pneumatic tire 1 includes a support structure 10 and a tread 50. Here, the support structure 10 supports the load from the vehicle. Further, the tread 50 is located outside the support structure 10 in the tire radial direction X and extends along the tire circumferential direction C. The details of the structure of the non-pneumatic tire 1 will be described later.

[0013] The support structure 10 contains a resin and an additive. Here, the additive includes a phenolic antioxidant and a hindered amine light stabilizer. Further, the hindered amine light stabilizer has an amino ether group. Therefore, even when the non-pneumatic tire 1 is used for a long period of time, the change in the breaking stress of the support structure 10 is suppressed and the discoloration of the support structure 10 is suppressed. It is presumed that this is because the antagonistic action with the phenolic antioxidant is suppressed due to the hindered amine light stabilizer having an amino ether group. Here, the phenolic antioxidant suppresses the oxidation of the resin, and the hindered amine light stabilizer suppresses the photo-degradation of the resin.

[0014] Examples of the phenolic antioxidant include dibutylhydroxytoluene. Examples of commercially available products of phenolic antioxidants include Adeka Stab AO-20, AO-60, AO-80 (above, manufactured by ADEKA), Sumilizer GA-80, GS (above, manufactured by Sumitomo Chemical).

[0015] The content of the phenolic antioxidant in the support structure 10 is, for example, 0.05% by mass or more and 0.9% by mass or less.

[0016] The pK of the hindered amine light stabilizer b is preferably 8 or more, and more preferably 9 or more. When the pK of the hindered amine light stabilizer b is 8 or more, the discoloration of the support structure 10 is suppressed even when the non-pneumatic tire 1 is used for a long period of time. Note that the pK of the hindered amine light stabilizer b is, for example, 10 or less. Here, K b is the base dissociation constant.

[0017] The molecular weight of the hindered amine light stabilizer is preferably 500 or more, and more preferably 800 or more. When the molecular weight of the hindered amine light stabilizer is 500 or more, even if the non-pneumatic tire 1 is used for a long period of time, the change in the breaking stress of the support structure 10 is suppressed.

[0018] Examples of commercially available hindered amine light stabilizers include, for example, Adeka Stab LA-81 (manufactured by ADEKA) with a molecular weight of 681, pK b 9.6, and Tinuvin 123 (manufactured by BASF) with a molecular weight of 737.

[0019] The content of the hindered amine light stabilizer in the support structure 10 is, for example, 0.05% by mass or more and 0.9% by mass or less.

[0020] The mass ratio of the hindered amine light stabilizer to the phenolic antioxidant in the additive is preferably 0.2 or more and 10 or less, and more preferably 0.2 or more and 3.0 or less. When the mass ratio of the hindered amine light stabilizer to the phenolic antioxidant in the additive is 0.2 or more, even if the non-pneumatic tire 1 is used for a long period of time, the change in the breaking stress of the support structure 10 is suppressed. On the other hand, when the mass ratio of the hindered amine light stabilizer to the phenolic antioxidant in the additive is 10 or less, even if the non-pneumatic tire 1 is used for a long period of time, the discoloration of the support structure 10 is suppressed.

[0021] The additive may further contain an ultraviolet absorber. Thereby, even if the non-pneumatic tire 1 is used for a long period of time, the change in the breaking stress of the support structure 10 is suppressed. Here, the ultraviolet absorber suppresses the photo-degradation of the resin.

[0022] The ultraviolet absorber is not particularly limited, and examples thereof include benzotriazole-based ultraviolet absorbers, triazine-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, and cyanoacrylate-based ultraviolet absorbers.

[0023] Examples of commercially available benzotriazole-based ultraviolet absorbers include Adeka Stab LA-29, 32, 36 (manufactured by ADEKA), and Tinuvin 234 (manufactured by BASF). Examples of commercially available triazine-based ultraviolet absorbers include Adeka Stab LA-46 (manufactured by ADEKA) and Tinuvin 1577 (manufactured by BASF). Examples of commercially available benzophenone-based ultraviolet absorbers include Adeka Stab 1413 (manufactured by ADEKA). Examples of commercially available cyanoacrylate-based ultraviolet absorbers include Uvinul 3035 (manufactured by BASF).

[0024] The content of the ultraviolet absorber in the support structure 10 is, for example, 0.1% by mass or more and 0.3% by mass or less.

[0025] The content of the additive in the support structure 10 is preferably 0.1% by mass or more and 1.8% by mass or less, and more preferably 0.2% by mass or more and 1.0% by mass or less. When the content of the additive in the support structure 10 is 0.1% by mass or more, even when the non-pneumatic tire 1 is used for a long period of time, changes in the breaking stress and discoloration of the support structure 10 are suppressed. On the other hand, when the content of the additive in the support structure 10 is 1.8% by mass or less, even when the non-pneumatic tire 1 is used for a long period of time, changes in the breaking stress of the support structure 10 are suppressed.

[0026] The resin contained in the support structure 10 is not particularly limited, and examples include thermoplastic elastomers, crosslinked rubbers, and other resins, and two or more thereof may be used in combination.

[0027] Examples of the thermoplastic elastomer include, for example, polyester elastomer, polyolefin elastomer, polyamide elastomer, polystyrene elastomer, polyvinyl chloride elastomer, and polyurethane elastomer. As the rubber constituting the crosslinked rubber, either natural rubber or synthetic rubber can be used. Examples of the synthetic rubber include, for example, styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IIR), nitrile rubber (NBR), hydrogenated nitrile rubber (hydrogenated NBR), chloroprene rubber (CR), ethylene propylene rubber (EPDM), fluororubber, silicone rubber, acrylic rubber, and urethane rubber. As the other resins, either thermoplastic resin or thermosetting resin can be used. Examples of the thermoplastic resin include, for example, polyethylene resin, polystyrene resin, and polyvinyl chloride resin. Examples of the thermosetting resin include, for example, epoxy resin, phenol resin, polyurethane resin, silicone resin, polyimide resin, and melamine resin. Among these, polyurethane is preferable from the viewpoints of the moldability and processability of the support structure 10.

[0028] In addition to the resin and the additive, the support structure 10 may further contain a reinforcing material, a pigment, and the like.

[0029] The support structure 10 can be obtained, for example, by thermosetting a thermosetting resin composition containing a resin precursor and an additive using a mold. When the resin is a urethane resin, for example, a urethane prepolymer and a polyol are used as the precursors of the urethane resin. Hereinafter, the precursors of the urethane resin will be described.

[0030] The urethane prepolymer is a polymer obtained by polyaddition of an excess of polyisocyanate and a polyol, and has an isocyanate group at the terminal.

[0031] The polyisocyanate is not particularly limited as long as it has a plurality of isocyanate groups. For example, aromatic diisocyanates such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, polymeric MDI, carbodiimide-modified MDI, 1,5-naphthalene diisocyanate, 1,4-phenylene diisocyanate (PPDI), 1,3-phenylene diisocyanate, 1,4-xylylene diisocyanate, 1,3-xylylene diisocyanate; aliphatic diisocyanates such as ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate; alicyclic diisocyanates such as 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, norbornane diisocyanate, etc. may be mentioned, and two or more of them may be used in combination. Among these, 1,4-phenylene diisocyanate is preferred.

[0032] The polyol used for the synthesis of the urethane prepolymer is not particularly limited as long as it has a plurality of hydroxyl groups. For example, low molecular weight polyols, polyether polyols, polyester polyols may be mentioned, and two or more of them may be used in combination. Among these, low molecular weight polyols and polyether polyols are preferred.

[0033] Examples of the low molecular weight polyol include aliphatic diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, methyloctanediol, 1,9-nonanediol; alicyclic diols such as 1,4-cyclohexanediol; aromatic diols such as 1,4-bis(β-hydroxyethoxy)benzene, hydroquinone, resorcinol, chlorohydroquinone, bromohydroquinone, methylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl methane, bisphenol A, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,2-bis(4-hydroxyphenoxy)ethane, 1,4-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, etc. Two or more of these may be used in combination. Among these, 1,4-butanediol is preferred.

[0034] Examples of the polyether polyol include polytetramethylene glycol, polyethylene glycol, and polypropylene glycol. Two or more of these may be used in combination. Among these, polytetramethylene glycol is preferred. The number average molecular weight of the polyether polyol is, for example, 200 or more and 3000 or less.

[0035] Examples of the polyester polyol include polyadipate glycol, polyphthalate glycol, polycarbonate diol, and polycaprolactone polyol. The number average molecular weight of the polyester polyol is, for example, 200 or more and 3000 or less.

[0036] The polyol used as a precursor of the urethane resin is the same as the polyol used in the synthesis of the urethane prepolymer, but it may be the same as or different from the polyol used in the synthesis of the urethane prepolymer.

[0037] The non-pneumatic tire 1 is obtained, for example, by vulcanizing and adhering a support structure 10 and a tread rubber composition using a vulcanizing adhesive. Specifically, first, the outer peripheral surface of the outer annular portion 30 of the support structure 10 is roughened. Thereby, the adhesiveness between the support structure 10 and the tread 50 is increased. The method for roughening the outer peripheral surface of the outer annular portion 30 is not particularly limited, and examples thereof include buffing. Next, a vulcanizing adhesive is applied to the roughened outer peripheral surface of the outer annular portion 30 and dried. Next, after winding the tread rubber composition around the outer peripheral surface of the outer annular portion 30 to which the vulcanizing adhesive has been applied, vulcanizing adhesion is performed.

[0038] The tread rubber composition includes, for example, natural rubber and carbon black, and may further include sulfur, silica, etc. Here, the tread rubber composition may include synthetic rubber such as polyisoprene rubber and styrene-butadiene rubber together with or instead of natural rubber.

[0039] Hereinafter, the details of the structure of the non-pneumatic tire 1 will be described. FIG. 1 is a side view of the non-pneumatic tire 1 viewed from the side in a direction parallel to the tire rotation axis (tire meridian), that is, in the direction along the front and back of the paper in FIG. 1. The non-pneumatic tire 1 shown in FIG. 1 is in an unloaded state. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1. FIG. 3 is a partial perspective view of the non-pneumatic tire 1 looking obliquely at the portion shown in FIG. 2.

[0040] In FIGS. 1 and 3, C indicates the tire circumferential direction. In FIGS. 1 to 3, X indicates the tire radial direction. In FIGS. 2 and 3, Y indicates the tire width direction. In FIG. 1, the tire width direction Y is the front and back of the paper. In FIG. 2, E indicates the tire equatorial plane. In FIG. 2, the tire circumferential direction C is the front and back of the paper.

[0041] The tire circumferential direction C is the direction around the tire rotation axis and is the same as the direction in which the non-pneumatic tire 1 rotates. The tire radial direction X is the direction perpendicular to the tire rotation axis. The tire width direction Y is the direction parallel to the tire rotation axis. In FIGS. 2 and 3, one side of the tire width direction Y is shown as Y1, and the other side of the tire width direction Y is shown as Y2. The tire equatorial plane E shown in FIG. 2 is a plane orthogonal to the tire rotation axis and is located at the center of the tire width direction Y.

[0042] Note that the thickness of the inner annular portion 20 and the outer annular portion 30 is the dimension in the tire radial direction X. Also, the width of the inner annular portion 20 and the outer annular portion 30 is the dimension in the tire width direction Y shown in FIG. 2.

[0043] The inner annular portion 20 is an annular portion along the tire circumferential direction C that constitutes the inner peripheral portion of the non-pneumatic tire 1. The thickness and width of the inner annular portion 20 are set to be constant in order to improve uniformity. A tire wheel is disposed in the space on the inner peripheral side of the inner annular portion 20. The inner peripheral portion of the inner annular portion 20 is fitted and mounted on the outer peripheral portion of the rim of the tire wheel. When the inner annular portion 20 is mounted on the rim, the non-pneumatic tire 1 is mounted on the tire wheel. The inner peripheral surface of the inner annular portion 20 may be provided with a fitting portion composed of a convex portion, a groove, etc. for fitting with the rim.

[0044] The inner annular portion 20 transmits the rotation of the tire wheel to the spokes 40 and the outer annular portion 30. The thickness of the inner annular portion 20 is determined from the viewpoint of satisfying the function of sufficiently transmitting the rotational force to the spokes 40 while achieving weight reduction and durability. The thickness of the inner annular portion 20 is not particularly limited, but for example, it is preferably 2% or more and 7% or less of the tire section height H shown in FIG. 2, and more preferably 3% or more and 6% or less.

[0045] The inner diameter of the inner annular portion 20 is determined according to the dimensions of the rim of the tire wheel on which the non-pneumatic tire 1 is mounted, the use of the vehicle, and the like. For example, when assuming the replacement of a general pneumatic tire, the inner diameter of the inner annular portion 20 may be, for example, a dimension of 250 mm or more and 500 mm or less, but is not limited thereto.

[0046] The width of the inner annular portion 20 is appropriately determined according to the use of the vehicle on which the non-pneumatic tire 1 is mounted, the length of the axle, and the like. For example, when assuming the replacement of a general pneumatic tire, the width of the inner annular portion 20 may be a dimension of 100 mm or more and 300 mm or less, but is not limited thereto.

[0047] The outer annular portion 30 is an annular portion along the tire circumferential direction C that constitutes the outer peripheral portion of the non-pneumatic tire 1. The outer annular portion 30 is arranged concentrically with the inner annular portion 20 on the outer peripheral side of the inner annular portion 20. The thickness and width of the outer annular portion 30 are set to be constant in order to improve uniformity.

[0048] The outer annular portion 30 transmits the rotation of the inner annular portion 20 and the spokes 40 to the road surface via the tread 50. The thickness of the outer annular portion 30 is determined from the viewpoint of sufficiently transmitting the rotational force from the spokes 40 to the road surface while achieving weight reduction and durability. The thickness of the outer annular portion 30 is not particularly limited, but is preferably, for example, 2% or more and 7% or less of the tire cross-sectional height H shown in FIG. 2, and more preferably 2% or more and 5% or less.

[0049] The inner diameter of the outer annular portion 30 is appropriately determined according to the dimensions of the rim of the tire wheel on which the non-pneumatic tire 1 is mounted, the use of the vehicle, and the like. For example, when assuming the replacement of a general pneumatic tire, the inner diameter of the outer annular portion 30 may be a dimension of 420 mm or more and 750 mm or less, but is not limited thereto.

[0050] The width of the outer annular portion 30 is appropriately determined according to the use of the vehicle to which the non-pneumatic tire 1 is mounted, etc. For example, when assuming an alternative to a general pneumatic tire, the width of the outer annular portion 30 may be a dimension such as 100 mm or more and 300 mm or less, but is not limited thereto.

[0051] The plurality of spokes 40 connect the inner annular portion 20 and the outer annular portion 30. The inner annular portion 20 and the outer annular portion 30 connected by the plurality of spokes 40 are arranged concentrically with each other. Each of the plurality of spokes 40 is independently arranged along the tire circumferential direction C. As shown in FIG. 1, when the non-pneumatic tire 1 is in an unloaded state, the plurality of spokes 40 extend linearly in the radial direction substantially parallel to the tire radial direction X in a side view.

[0052] As shown in FIGS. 2 and 3, the plurality of spokes 40 of the present embodiment include a plurality of first spokes 41 and a plurality of second spokes 42. The extending direction of both the first spoke 41 and the second spoke 42 is not parallel to the tire radial direction X when viewed in the direction along the tire circumferential direction C. The first spoke 41 is inclined toward one side in the tire axial direction, that is, in the tire width direction Y. The second spoke 42 is inclined toward the side opposite to the first spoke 41. The first spoke 41 and the second spoke 42 are alternately arranged in the tire circumferential direction C.

[0053] Specifically, as shown in FIGS. 2 and 3, the first spoke 41 extends obliquely from the Y1 side, which is one side in the tire width direction Y of the outer annular portion 30, toward the Y2 side, which is the other side in the tire width direction Y of the inner annular portion 20. The second spoke 42 extends obliquely from the Y2 side, which is the other side in the tire width direction Y of the outer annular portion 30, toward the Y1 side, which is one side in the tire width direction Y of the inner annular portion 20.

[0054] The inclination angles of the first spoke 41 and the second spoke 42 are the same. Therefore, the first spoke 41 and the second spoke 42 adjacent to each other in the tire circumferential direction C are arranged in a substantially X shape when viewed from the direction along the tire circumferential direction C. As shown in FIG. 2, the first spoke 41 and the second spoke 42 are inclined at an angle θ with respect to the tire width direction Y, and the angle θ is preferably, for example, 30° or more and 60° or less.

[0055] As shown in FIG. 2, each of the first spoke 41 and the second spoke 42 in the state viewed from the direction along the tire circumferential direction C has the same shape symmetric with respect to the tire equatorial plane E. Therefore, hereinafter, when there is no need to distinguish between the first spoke 41 and the second spoke 42 and they can be collectively described, the first spoke 41 and the second spoke 42 are collectively referred to as the spoke 40.

[0056] The spoke 40 is plate-shaped and extends obliquely at an angle of the angle θ as described above from the inner annular portion 20 toward the outer annular portion 30. As shown in FIG. 3, the spoke 40 has a plate thickness t along the tire circumferential direction that is smaller than the plate width w, and the direction of the plate thickness t is along the tire circumferential direction C. That is, the spoke 40 is formed in a plate shape extending along the plane of the tire radial direction X and the tire width direction Y. Here, the plate width w is, as also shown in FIG. 2, the dimension in the direction orthogonal to the inclination direction in which the spoke 40 extends when the spoke 40 is viewed from the direction along the tire circumferential direction C. In the present embodiment, the plate thickness t of all the spokes 40 is the same. Also, the plate width w of all the spokes 40 is the same.

[0057] Since the spoke 40 is in the shape of a long plate, even if the plate thickness t is made thin, the durability of the spoke 40 can be improved by setting the plate width w wide. Further, by reducing the plate thickness t and increasing the number of the spokes 40, the interval between the spokes 40 adjacent to each other in the tire circumferential direction C can be reduced while maintaining the rigidity of the entire non-pneumatic tire 1. Thereby, the ground pressure during tire rolling by the spokes 40 is dispersed, and the ground pressure can be reduced.

[0058] Note that although the spoke 40 is parallel to the tire radial direction X in side view, the spoke 40 may be arranged obliquely with respect to the tire radial direction X so as to intersect the tire radial direction X in side view.

[0059] As shown in FIGS. 2 and 3, the first spoke 41 has a first inner connection portion 411 connected to the tire width direction Y2 side of the inner annular portion 20 and a first outer connection portion 412 connected to the tire width direction Y1 side of the outer annular portion 30. The second spoke 42 has a second inner connection portion 421 connected to the tire width direction Y1 side of the inner annular portion 20 and a second outer connection portion 422 connected to the tire width direction Y2 side of the outer annular portion 30. Each of the first outer connection portion 412 and the second outer connection portion 422 is an example of a connection portion of the spoke 40 connected to the outer annular portion 30 in the present embodiment.

[0060] As shown in FIG. 2, the first inner connection portion 411 of the first spoke 41 has a shape that widens along the tire width direction Y as it approaches the inner annular portion 20. The side surface 411a on the tire width direction Y2 side of the first inner connection portion 411 extends while gently curving to the end portion 20b on the tire width direction Y2 side of the inner annular portion 20. The side surface 411b on the tire width direction Y1 side of the first inner connection portion 411 curves and extends toward the tire width direction Y1 side to the position of the tire equatorial plane E of the inner annular portion 20.

[0061] The first outer connection portion 412 of the first spoke 41 has the same shape as the first inner connection portion 411 and has a shape that widens along the tire width direction as it approaches the outer annular portion 30. The side surface 412a on the tire width direction Y1 side of the first outer connection portion 412 extends while gently curving to the end portion 30a on the tire width direction Y1 side of the outer annular portion 30. The side surface 412b on the tire width direction Y2 side of the first outer connection portion 412 curves and extends toward the tire width direction Y2 side to the position of the tire equatorial plane E of the outer annular portion 30.

[0062] The first inner connection part 411 is provided in a region that is half of the inner annular part 20 on the tire width direction Y2 side. The first outer connection part 412 is provided in a region that is half of the outer annular part 30 on the tire width direction Y1 side.

[0063] As shown in FIG. 2, the second inner connection part 421 of the second spoke 42 has a shape that widens along the tire width direction Y as it approaches the inner annular part 20. The side surface 421a on the tire width direction Y1 side of the second inner connection part 421 extends smoothly while curving up to the end 20a on the tire width direction Y1 side of the inner annular part 20. The side surface 421b on the tire width direction Y2 side of the second inner connection part 421 curves and extends toward the tire width direction Y2 side up to the position of the tire equatorial plane E of the inner annular part 20.

[0064] The second outer connection part 422 of the second spoke 42 has the same shape as the second inner connection part 421, and has a shape that widens along the tire width direction as it approaches the outer annular part 30. The side surface 422a on the tire width direction Y2 side of the second outer connection part 422 extends smoothly while curving up to the end 30b on the tire width direction Y2 side of the outer annular part 30. The side surface 422b on the tire width direction Y1 side of the second outer connection part 422 curves and extends toward the tire width direction Y1 side up to the position of the tire equatorial plane E of the outer annular part 30.

[0065] The second inner connection part 421 is provided in a region that is half of the inner annular part 20 on the tire width direction Y1 side. The second outer connection part 422 is provided in a region that is half of the outer annular part 30 on the tire width direction Y2 side.

[0066] As described above, the plate thickness t of all the spokes 40 in the present embodiment is the same. The dimension of the plate thickness t is not particularly limited, but in order for the spoke 40 to sufficiently receive the rotational force from the inner annular part 20 and the outer annular part 30 and be able to flexibly deform moderately when receiving a load, it is preferably 1 mm or more and 30 mm or less, and more preferably 5 mm or more and 25 mm or less.

[0067] As described above, the plate width w of all the spokes 40 in the present embodiment is the same. The plate width w of the spoke 40 is not particularly limited, but in order to sufficiently receive the rotational force from the inner annular portion 20 and the outer annular portion 30 and to be able to flexibly deform appropriately when receiving a load, it is preferably 5 mm or more and 25 mm or less, and more preferably 10 mm or more and 20 mm or less. Further, from the viewpoint of being able to disperse the ground pressure while improving the durability, the plate width w is preferably 110% or more of the plate thickness t, and more preferably 115% or more.

[0068] The number of the spokes 40 is preferably 80 or more and 300 or less, and more preferably 100 or more and 200 or less, from the viewpoint of being able to sufficiently support the load from the vehicle, being able to achieve weight reduction, and being able to improve both power transmission performance and durability.

[0069] The tread 50 is provided on the outer peripheral surface of the outer annular portion 30 and constitutes the outermost peripheral portion of the non-pneumatic tire 1. The tread 50 has a tread surface 51 that contacts the road surface on its outer peripheral surface. A tread pattern formed by a plurality of grooves and land portions is provided on the tread surface 51 of the tread 50 in the same manner as a conventional pneumatic tire.

[0070] Note that the tread 50 may have a structure in which a plurality of vulcanized rubber layers having different components and characteristics are laminated (for example, two layers or three layers).

[0071] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and the above embodiments may be appropriately modified within the scope of the gist of the present invention. For example, a reinforcing layer may be embedded in the outer annular portion 30.

[0072] The configuration of the embodiment of the present invention is as follows.

[0073] (1) A non-pneumatic tire comprising a support structure and a tread located radially outside the support structure and extending along the tire circumferential direction, wherein the support structure contains a resin and an additive, the additive contains a phenolic antioxidant and a hindered amine light stabilizer, and the hindered amine light stabilizer has an amino ether group.

[0074] (2) The non-pneumatic tire according to (1), wherein the hindered amine light stabilizer has a pK b of 8 or more.

[0075] (3) The non-pneumatic tire according to (1) or (2), wherein the hindered amine light stabilizer has a molecular weight of 500 or more.

[0076] (4) The non-pneumatic tire according to any one of (1) to (3), wherein the additive has a mass ratio of the hindered amine light stabilizer to the phenolic antioxidant of 0.2 or more and 10 or less.

[0077] (5) The non-pneumatic tire according to any one of (1) to (4), wherein the additive further contains an ultraviolet absorber.

[0078] (6) The non-pneumatic tire according to any one of (1) to (5), wherein the support structure has a content of the additive of 0.1% by mass or more and 1.8% by mass or less.

[0079] (7) A thermosetting resin composition used for manufacturing a support structure of a non-pneumatic tire, comprising a resin precursor and an additive, the additive contains a phenolic antioxidant and a hindered amine light stabilizer, and the hindered amine light stabilizer has an amino ether group.

Examples

[0080] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the embodiments. Since it is difficult to directly measure the change in breaking stress and discoloration of the support structure, the change in breaking stress and discoloration of a test piece simulating the support structure were measured.

[0081] [Examples 1 to 13, Comparative Examples 1 and 2] Using a hybrid mixer (manufactured by Shinchi), a urethane resin precursor, an antioxidant, a light stabilizer, and an ultraviolet absorber were mixed at the compounding [mass%] shown in Tables 1 and 2 to obtain a thermosetting resin composition. Next, after injecting the thermosetting resin composition into a mold, it was thermoset at 130 °C for 16 hours to obtain test pieces with a width of 100 mm, a length of 200 mm, and a thickness of 2 mm.

[0082] Here, as the urethane resin precursor, a mixture (mass ratio 123:7:3) of Adiprene LFP E560 (manufactured by LANXESS) as a urethane prepolymer, Vibracure A250 (manufactured by LANXESS) as a low molecular polyol, and PTMG1000 (manufactured by Mitsubishi Chemical) as a polyether polyol was used. The details of the antioxidant, light stabilizer, and ultraviolet absorber are as follows. Antioxidant: Phenolic antioxidant Adeka Stab AO-60 (manufactured by ADEKA) Light stabilizer (A): Hindered amine light stabilizer (molecular weight 681) Adeka Stab LA-81 (manufactured by ADEKA) having an amino ether group Light stabilizer (B): Hindered amine light stabilizer (pK b 9.6, molecular weight 737) Tinuvin 123 (manufactured by BASF) Light stabilizer (C): Hindered amine light stabilizer Adeka Stab LA-63P (manufactured by ADEKA) having no amino ether group Ultraviolet absorber: Benzotriazole-based ultraviolet absorber Adeka Stab LA-32 (manufactured by ADEKA)

[0083] [Light source exposure test] In accordance with JIS K7350-2, a light source exposure test was carried out using a super xenon weather meter (manufactured by Suga Test Instruments Co., Ltd.) under the following conditions. Atmospheric temperature: 38 °C Atmospheric humidity: 50% RH Black panel temperature: 65 °C Wavelength: 300 - 400 nm Illuminance: 180 W / m 2 Test time: 240 hours

[0084] [Change rate of breaking stress of test piece] The breaking stress of the test piece before and after the light source exposure test was measured, and the ratio of the breaking stress of the test piece after the light source exposure test to the breaking stress of the test piece before the light source exposure test, that is, the change rate of the breaking stress of the test piece, was determined. The change rate of the breaking stress of the test piece was judged according to the following criteria. A: When the change rate of the breaking stress of the test piece is 80% or more and less than 120% B: When the change rate of the breaking stress of the test piece is 50% or more and less than 80% or 120% or more and less than 150% C: When the change rate of the breaking stress of the test piece is less than 50% or 150% or more

[0085] [Color difference of test piece] In accordance with JIS Z8781-6 (CIEDE2000 color difference formula), using a color difference meter CR-400 (manufactured by Konica Minolta), with the test piece before the light source exposure test as the reference color, the color difference ΔE00 after the light source exposure test was measured. The color difference of the test piece was judged according to the following criteria. A: When ΔE00 is less than 18 B: When ΔE00 is 18 or more

[0086] Tables 1 and 2 show the evaluation results of the test pieces.

[0087] [Table 1]

[0088] [Table 2]

[0089] From Table 1, it can be seen that the test pieces of Examples 1 to 13 have small change rates of breaking stress and color differences. In contrast, for the test piece of Comparative Example 1, since no additive is added, the change rate of breaking stress and the color difference are large. Also, for the test piece of Comparative Example 2, since the light stabilizer (C) does not have an amino ether group, the color difference is large. This is presumably because it is due to the antagonistic action between the light stabilizer (C) and the antioxidant.

Explanation of Signs

[0090] 1 Non-pneumatic tire 10 Support structure 20 Inner annular part 20a, 20b Ends 30 Outer annular part 30a, 30b Ends 40 Spoke 41 First spoke 42 Second spoke 411 First inner connection part 411a, 411b Sides 412 First outer connection part 412a, 412b Sides 421 Second inner connection part 421a, 421b Sides 422 Second outer connection part 422a, 422b Sides 50 Tread 51 Tread surface C Tire circumferential direction E Tire equatorial plane O Axis X Tire radial direction Y Tire width direction

Claims

1. A support structure and a tread located radially outside the support structure in the tire diameter direction and extending along the tire circumferential direction. The support structure includes a resin and an additive. The additive includes a phenolic antioxidant and a hindered amine light stabilizer. The hindered amine light stabilizer has an amino ether group, non-pneumatic tire.

2. The hindered amine light stabilizer has a pK ｂ of 8 or more, the non-pneumatic tire according to claim 1.

3. The hindered amine light stabilizer has a molecular weight of 500 or more, the non-pneumatic tire according to claim 1 or 2.

4. The additive has a mass ratio of the hindered amine light stabilizer to the phenolic antioxidant of 0.2 or more and 10 or less, the non-pneumatic tire according to claim 1 or 2.

5. The additive further includes an ultraviolet absorber, the non-pneumatic tire according to claim 1.

6. The support structure has a content of the additive of 0.1% by mass or more and 1.8% by mass or less, the non-pneumatic tire according to claim 1 or 2.

7. A thermosetting resin composition used for manufacturing a support structure of a non-pneumatic tire, including a resin precursor and an additive, the additive includes a phenolic antioxidant and a hindered amine light stabilizer, the hindered amine light stabilizer has an amino ether group, thermosetting resin composition.

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