Polyurethane flexible section-elongated composite spoke joint for non-pneumatic tires and method for manufacturing the same

Abstract

A method for manufacturing a polyurethane bend-to-elongated composite spoke joint for use in a non-pneumatic tire, a polyurethane bend-to-elongated composite spoke joint manufactured by this method, and a polyurethane bend-to-elongated composite spoke joint for use in a non-pneumatic tire. The method comprises polishing a first surface (end) of a cured elongated composite spoke and finally insert-molding a polyurethane bend onto the cured elongated composite spoke. Also disclosed are a non-pneumatic tire incorporating a polyurethane bend-to-elongated composite spoke joint manufactured by the disclosed method, obtained from the disclosed method, or otherwise disclosed herein. The polyurethane bend-to-elongated composite spoke joint has a specific peel strength.

Description

[Technical Field]

[0001] The present application relates to a polyurethane bent portion-elongated composite spoke joint assembly for use in non-pneumatic tires, a related method for manufacturing the polyurethane bent portion-elongated composite spoke joint assembly, and a non-pneumatic tire comprising the joint assembly. [Background Art]

[0002] Conventional (pneumatic) tires are inflated with air. Non-pneumatic tires can be considered airless because they support the weight of a vehicle and absorb impacts from road surfaces without relying on air inflation. Non-pneumatic tires offer advantages in terms of low maintenance and elimination of the risk of puncture. Various designs have been proposed for non-pneumatic tires, including those using a network of spokes connected to an inner rim-like structure and covered by an outer band or ring and a relatively thin rubber layer as a tread. In such designs, the spokes function to support the vehicle weight. [Summary of the Invention]

[0003] Disclosed herein are a polyurethane bent portion-elongated composite spoke joint assembly for use in non-pneumatic tires, a method of manufacturing the same, and a non-pneumatic tire incorporating the polyurethane bent portion-elongated composite spoke joint assembly.

[0004] In a first embodiment, a method is disclosed for manufacturing a polyurethane bend-to-elongated composite spoke joint for use in non-pneumatic tires. The method of the first embodiment includes providing a cured elongated composite spoke having an end having a first surface and a second surface, and comprising fibers selected from the group consisting of carbon fibers, glass fibers, aramid fibers, and combinations thereof, and an epoxy resin; polishing the first surface of the cured elongated composite spoke to produce a roughened first surface; and insert molding a polyurethane bend into at least a portion of the roughened first surface of the cured elongated composite spoke, thereby producing a polyurethane bend-to-elongated composite spoke joint having a peel strength of at least 70 pli (at least 12,000 N / m), preferably at least 90 pli (at least 16,000 N / m), and more preferably 17,000 N / m, with a peel strength of at least 100 pli, as determined using a 90-degree peel strength test (in accordance with ASTM D6892 / D903).

[0005] In a second embodiment, a polyurethane bend-to-elongated composite spoke joint manufactured by the method of the first embodiment is disclosed.

[0006] In a third embodiment, a non-pneumatic tire is disclosed that incorporates the polyurethane bend-to-elongated composite spoke joint of the second embodiment.

[0007] In a fourth embodiment, a polyurethane bend-to-elongated composite spoke joint for use in non-pneumatic tires is disclosed. This polyurethane bend-to-elongated composite spoke joint comprises a cured elongated composite spoke having an end having a first surface and a second surface, and composed of fibers selected from the group consisting of carbon fibers, glass fibers, aramid fibers, and combinations thereof, and an epoxy resin, and a polyurethane bend joined to the end of the cured elongated composite spoke on its first surface with a peel strength of at least 70 pli (at least 12,000 N / m), preferably at least 90 pli (at least 16,000 N / m), more preferably 17,000 N / m and at least 100 pli, as determined by a 90-degree peel strength test (in accordance with ASTM D6892 / D903), wherein the end of the elongated composite spoke has a roughened surface on at least its first surface below the joined polyurethane bend.

[0008] In the fifth embodiment, a non-pneumatic tire is disclosed that incorporates the polyurethane bend-to-slender composite spoke joint of the fourth embodiment. [Modes for carrying out the invention]

[0009] In a first embodiment, a method is disclosed for manufacturing a polyurethane bend-to-elongated composite spoke joint for use in non-pneumatic tires. The method of the first embodiment includes providing a cured elongated composite spoke having an end having a first surface and a second surface, comprising fibers selected from the group consisting of carbon fibers, glass fibers, aramid fibers, and combinations thereof, and an epoxy resin; polishing the first surface of the cured elongated composite spoke to produce a roughened first surface; and insert molding a polyurethane bend into at least a portion of the roughened first surface of the cured elongated composite spoke, thereby producing a polyurethane bend-to-elongated composite spoke joint having a peel strength of at least 70 pli (at least 12,000 N / m), preferably at least 90 pli (at least 16,000 N / m), and more preferably 17,000 N / m, with a peel strength of at least 100 pli, as determined using a 90-degree peel strength test (in accordance with ASTM D6892 / D903).

[0010] In a second embodiment, a polyurethane bend-to-elongated composite spoke joint manufactured by the method of the first embodiment is disclosed.

[0011] In a third embodiment, a non-pneumatic tire is disclosed that incorporates the polyurethane bend-to-elongated composite spoke joint of the second embodiment.

[0012] In a fourth embodiment, a polyurethane bend-to-elongated composite spoke joint for use in non-pneumatic tires is disclosed. This polyurethane bend-to-elongated composite spoke joint comprises a cured elongated composite spoke having an end having a first surface and a second surface, the cured elongated composite spoke being composed of fibers selected from the group consisting of carbon fibers, glass fibers, aramid fibers, and combinations thereof, and an epoxy resin, and a polyurethane bend joined to the end of the cured elongated composite spoke on its first surface with a peel strength of at least 70 pli (at least 12,000 N / m), preferably at least 90 pli (at least 16,000 N / m), more preferably 17,000 N / m and at least 100 pli, as determined by a 90-degree peel strength test (in accordance with ASTM D6892 / D903), wherein the end of the elongated composite spoke has a roughened surface on at least its first surface below the joined polyurethane bend.

[0013] In the fifth embodiment, a non-pneumatic tire is disclosed that incorporates the polyurethane bend-to-slender composite spoke joint of the fourth embodiment.

[0014] Uncured elongated composite spokes According to the first to fifth embodiments, an uncured elongated composite spoke is provided that will become part of a polyurethane bend elongated composite spoke joint. According to the first to fifth embodiments, the spoke is made of a composite material and has an elongated shape. It should be understood that the elongated composite spoke is cured before polishing (as described below). In certain embodiments of the first to fifth embodiments, the elongated shape of the spoke can be understood as a rod or rod-like. According to the first to fifth embodiments, the elongated composite spoke can be understood as having a first end and a second end, the first end being the end that attaches to the outer ring of a non-pneumatic tire (via a polyurethane bend), and the second end being the end that attaches (directly or indirectly) to the inner rim-like structure of the non-pneumatic tire. According to the first to fifth embodiments, the elongated composite spoke has an end (first end) having a first surface and a second surface. Polishing is used on at least the first surface of the spoke to produce a roughened first surface, as will be described in more detail below.

[0015] The spoke is elongated in that it extends radially between a first end and a second end. In certain embodiments of the first to fifth embodiments, the elongated composite spoke has a substantially rectangular cross-section including a first surface and a second surface facing the opposite side of the first surface. In other alternative embodiments of the first to fifth embodiments, the spoke may have any desired cross-sectional shape (e.g., circular, diamond-shaped, hexagonal, etc.) or a combination of different cross-sectional shapes. In the particular embodiments described above, if the cross-sectional shape is circular or elliptical, the first end of the spoke has a first flat surface and an optional second flat surface. In certain embodiments of the first to fifth embodiments, the spoke has a constant thickness between the first end and the second end. In alternative embodiments of the first to fifth embodiments, the thickness of the spoke may vary between the first end and the second end. For example, the spoke may have relatively thicker portions at the first and second ends and a relatively thinner portion between those ends.

[0016] According to the first to fifth embodiments, the composite spoke is composed of fibers selected from the group consisting of carbon fibers, glass fibers, aramid fibers, and combinations thereof, and epoxy resin. Therefore, the term composite material can be understood as referring to a combination of one or more such fibers and epoxy resin. In certain embodiments of the first to fifth embodiments, the composite spoke is composed of carbon fibers and epoxy resin. In other embodiments of the first to fifth embodiments, the composite spoke is composed of glass fibers and epoxy resin. In yet another embodiment of the first to fifth embodiments, the composite spoke is composed of aramid fibers and epoxy resin.

[0017] As described above, the elongated composite spokes of the first to fifth embodiments are made of a material containing epoxy resin. The properties of the epoxy resin can vary. In preferred embodiments of the first to fifth embodiments, the epoxy resin of the cured elongated composite spoke has a curing time of 15 minutes or less at 150°C (e.g., 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5 minutes or less), 5 to 15 minutes at 150°C, preferably 12 minutes or less at 150°C (e.g., 12, 11, 10, 9, 8, 7, 6, 5 minutes or less), or 5 to 12 minutes at 150°C (i.e., pre-cured or uncured form). In other embodiments of the first to fifth embodiments, the epoxy resin of the uncured elongated composite spokes has a curing time (i.e., pre-curing or uncured form) of more than 15 minutes at 150°C (e.g., 16 minutes, 30 minutes, 45 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, or more), 16 minutes to 24 hours at 150°C, or 16 minutes to 6 hours (e.g., 16 minutes, 30 minutes, 45 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours). It should be understood that the same epoxy resin is present in the polyurethane bend-elongated composite spoke joint and the elongated spokes present in non-pneumatic tires incorporating this joint.

[0018] polishing As described above, the method of the first embodiment includes polishing at least the first surface of the uncured composite spoke in order to produce a roughened surface on at least the first surface of the uncured composite spoke. In a particular embodiment of the first embodiment, the method includes polishing only the first surface of the uncured composite spoke in order to produce a roughened surface on the first surface of the uncured composite spoke. In other embodiments of the first embodiment, the method includes polishing both the first and second surfaces of the uncured composite spoke in order to produce a roughened surface on both the first and second surfaces of the uncured composite spoke joint, and in a particular such embodiment, the polishing includes polishing the entire outer surface of the first end of the elongated spoke (i.e., both the first and second surfaces, as well as any other surface between these two surfaces). As will be apparent from the following description (e.g., insert molding), the polyurethane bend-elongated composite spoke joint of the second and fourth embodiments includes a roughened surface (resulting from polishing) on ​​at least its first surface (at the first end) that lies beneath the joined polyurethane bend and facilitates a secure bond of the polyurethane bend. The non-pneumatic tire of the third embodiment incorporates the polyurethane bend-elongated composite spoke joint of the second embodiment and therefore includes the same roughened surface as the second embodiment. It should be understood that the aforementioned polishing details may also be used to manufacture the polyurethane bend-elongated composite spoke joints of the second and fourth embodiments, as well as the joints used in the non-pneumatic tires of the third and fifth embodiments.

[0019] According to the method of the first embodiment, the details of polishing may vary. In certain embodiments of the first embodiment, polishing includes grit blasting. In certain such embodiments, polishing consists of grit blasting. In other embodiments of the first embodiment, polishing includes using abrasive paper to produce a roughened surface. In certain such embodiments, polishing consists of using abrasive paper to produce a roughened surface. It should be understood that the aforementioned polishing details may also be used to manufacture polyurethane bend-elongated composite spoke joints of the second and fourth embodiments, and joints used in non-pneumatic tires of the third and fifth embodiments.

[0020] In the first embodiment, in which polishing includes or consists of grit blasting, the specific particles used, particle size, and pressure applied during grit blasting may vary. In the particular embodiment of the first embodiment, in which polishing includes or consists of grit blasting, the grit blast uses particles selected from the group consisting of aluminum oxide, alumina zirconia, silicon carbide, silica sand, garnet, steel, iron, quartz, walnut shells, and combinations thereof. In the preferred embodiment of the first embodiment, in which polishing includes or consists of grit blasting, the grit blast uses particles containing aluminum oxide. In the embodiment of the first embodiment, in which polishing includes or consists of grit blasting, the size of the particles used in grit blasting may vary. In certain embodiments of the first embodiment in which polishing includes or consists of grit blasting, the grit blasting includes using particles having a grit of 50 to 120 (e.g., 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, or 120 grit) or 330 to 120 microns (e.g., 330, 320, 310, 300, 290, 280, 270, 260, 250, 240, 230, 220, 210, 200, 190, 180, 170, 160, 150, 140, 130, or 120 microns). In embodiments of the first embodiment in which polishing includes or consists of grit blasting, various pressures may be applied during grit blasting. In certain embodiments of the first embodiment, where polishing includes or consists of grit blasting, pressures of 30 to 80 psi (e.g., 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80 psi) or 200 to 550 kPa (e.g., 200, 250, 300, 350, 400, 450, 500, or 550 kPa) are used.In certain embodiments of the first embodiment, where polishing includes or consists of grit blasting, the grit blast uses one or more types of particles as described above in combination with the grit size as described above. In other embodiments of the first embodiment, where polishing includes or consists of grit blasting, the grit blast uses one or more types of particles as described above having the grit size as described above and uses the pressure as described above. In other embodiments of the first embodiment, where polishing includes or consists of grit blasting, the grit blast uses one or more types of particles as described above in combination with the use of the pressure as described above. In yet another embodiment of the first embodiment, where polishing includes or consists of grit blasting, the grit blast uses particles having the grit size as described above in combination with the pressure as described above. It should be understood that the foregoing details regarding particles may also be used to manufacture the polyurethane bend-elongated composite spoke joints of the second and fourth embodiments, and the joints used in the non-pneumatic tires of the third and fifth embodiments.

[0021] In the first embodiment, in the embodiment in which polishing includes or consists of using abrasive paper, the specific particles used and their sizes may vary. In the first embodiment, in the embodiment in which polishing includes or consists of using abrasive paper, the abrasive paper contains particles selected from the group consisting of aluminum oxide, alumina zirconia, silicon carbide, silica sand, garnet, steel, iron, quartz, walnut shell, and combinations thereof. In certain embodiments of the first embodiment in which polishing includes or consists of using abrasive paper, the abrasive paper includes using particles having a grit of 50 to 120 (e.g., 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, or 120) or 330 to 120 microns (e.g., 330, 320, 310, 300, 290, 280, 270, 260, 250, 240, 230, 220, 210, 200, 190, 180, 170, 160, 150, 140, 130, or 120 microns). In embodiments of the first embodiment in which polishing includes or consists of using abrasive paper, the pressure used with the abrasive paper may vary. In the embodiments of the first embodiment in which polishing includes or consists of using abrasive paper, the pressure used corresponds to the pressure described above for grit blasting. In certain embodiments of the first embodiment in which polishing includes or consists of using abrasive paper, the abrasive paper has one or more types of particles as described above, in combination with particles having the grit as described above. In certain such embodiments, the abrasive paper is also used with one of the pressures described above. It should be understood that the foregoing details regarding particles may also be used to manufacture the polyurethane bend-elongated composite spoke joints of the second and fourth embodiments, and the joints used in the non-pneumatic tires of the third and fifth embodiments.

[0022] Roughened surface As described above, the method of the first embodiment uses polishing to produce a roughened surface on the surface of a hardened elongated composite spoke. According to the first embodiment, the roughened surface is produced on the surface of the hardened elongated spoke or multiple surfaces on which polishing is used. The locations on which polishing is used include at least a first surface of the hardened elongated composite spoke, and in certain embodiments, other surfaces of the hardened elongated composite spoke as described in detail above. In other words, if only the first surface of the hardened elongated composite spoke is polished, then only the first surface of the hardened elongated composite spoke will have a roughened surface.

[0023] According to the first to fifth embodiments, the composition and roughness of the roughened surface may vary depending on the type of polishing used. The roughness of the textured imprint surface can be determined by profilometry (i.e., using a Profilometer) using standard methods such as ISO 4287 and commercially available equipment, including portable surface roughness testers, such as those available from Taylor Hobson, such as the Surtronic® Duo. Exemplary values ​​obtained by profilometry include the average roughness (Ra), which can be understood as the arithmetic mean of the absolute values ​​of the profile heights over the evaluation length, and the average maximum profile height or average maximum profile height (Rz), which can be understood as the average of continuous values ​​of Rti calculated over the evaluation length. Rz is the same as Rz(DIN) when there are five sampling lengths within the evaluation length. The evaluation length is the length over which the values ​​of the surface parameters are evaluated, and is also called the assessment length. Rti refers to the maximum height within the sampling length and can be understood as the vertical distance between the highest and lowest points of the profile within the sampling length. The sampling length is the nominal wavelength used to separate roughness and waviness. The evaluation length refers to the total length over which the surface parameter values ​​are evaluated. The Ra and Rz measurements referred to herein were taken using a Surtronic® Duo portable surface roughness tester configured with a diamond stylus with a radius of 5 micrometers (200 microinches), a gauge force of 200 mg, a skid gauge measurement type, a Gaussian filter type, a 0.8 mm filter cutoff, an evaluation or cross-sectional length of 4 mm (0.157 inches), an evaluation or cross-sectional speed of 2 mm / sec (0.08 inches / sec), and a continuous measurement mode over the cross-sectional length.

[0024] In certain embodiments of the first to fifth embodiments, the roughened surface is determined by profilometry as described above, and is 50 to 200 microinches (e.g., 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200 microinches), or 1.3 to 5 micrometers (e.g., 1.3, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 micrometers), preferably 70 to 170 microinches. For example, it has an average roughness Ra of 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, or 170 microinches), or 2 to 4 micrometers (for example, 2, 2.5, 3, 3.5, or 4 micrometers), more preferably 90 to 150 microinches (for example, 90, 100, 110, 120, 130, 140, or 150 microinches), or 2.3 to 3.8 micrometers (for example, 2.3, 2.5, 3, 3.5, or 3.8 micrometers). In certain embodiments of the first to fifth embodiments, the roughened surface is determined by profilometry as described above, and is 300 to 1000 microinches (e.g., 300, 400, 500, 600, 700, 800, 900, or 1000 microinches), or 8 to 25 micrometers (e.g., 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 micrometers), preferably 400 to 800 microinches (e.g., 400, 450, 500, 550, 600, The profile has an average maximum height or average maximum profile height Rz of 650, 700, 750, or 800 microinches, or 10 to 20 micrometers (e.g., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 micrometers), more preferably 500 to 700 microinches (e.g., 500, 525, 550, 575, 600, 625, 650, 675, or 700 microinches), or 13 to 18 micrometers (e.g., 13, 14, 15, 16, 17, or 18 micrometers).In certain embodiments of the first to fifth embodiments, the roughened surface has a mean surface roughness Ra and a mean maximum profile height Rz that conform to the respective ranges described above, preferably the respective preferred ranges described above, and more preferably the respective more preferred ranges described above.

[0025] Insert molding The method of the first embodiment involves insert molding a polyurethane bend onto at least a portion of the roughened surface (of a cured elongated composite spoke). As will be described in more detail below, the insert molding results in a polyurethane bend-elongated composite spoke joint, where the polyurethane bend is joined to the end of the cured elongated composite spoke on the roughened surface (i.e., at least the first surface of the spoke). In a preferred embodiment of the first embodiment, the insert molding is performed immediately after polishing (i.e., without applying any surface treatment to the roughened surface). Surface treatment means any chemical treatment (e.g., application of adhesive or activator) and mechanical treatment (e.g., grit blasting or sanding) on ​​the roughened surface prior to insert molding. In other words, in such embodiments, the roughened surface is not surface treated before insert molding. It should be understood that the aforementioned details of insert molding may also be used to manufacture the polyurethane bend-elongated composite spoke joints of the second and fourth embodiments, as well as the joints used in non-pneumatic tires of the third and fifth embodiments.

[0026] As used herein, insert molding refers to an injection molding method in which molten or liquid materials are added to a mold, and then they are cooled and solidified. As part of insert molding, a component is present in the mold, and when the molten or liquid material is added to the mold, the material flows over the component and the mold, not only around the mold walls, but also around or on the component parts, thereby forming a bond with the component parts. According to the first embodiment disclosed herein, the component present in the mold for insert molding is at least a part of the (first) end portion of the elongated composite spoke, and the molten or liquid material is polyurethane. More specifically, the elongated composite spoke is present in the mold to the extent necessary to allow the polyurethane material to form a bond with the roughened surface (on at least the first surface of the end portion of the elongated composite spoke). It should be understood that the foregoing details of insert molding may also be used to manufacture the polyurethane bend-elongated composite spoke joint assemblies of the second and fourth embodiments, and the joint assemblies used in the non-pneumatic tires of the third and fifth embodiments. In certain embodiments of the first embodiment, the polyurethane material used is liquid at room temperature, or at least injectable. In other embodiments of the first embodiment, the polyurethane material is gel or solid at room temperature.

[0027] In general, it can be understood that a polyurethane such as the polyurethane used for insert-molding a bend on a roughened surface of an elongated composite spoke is a polymer composed of organic units linked by carbamate (urethane) bonds. Polyurethanes can be produced from a wide range of starting materials. As described herein, a polyurethane suitable for use (for insert molding) at a bend comprises an isocyanate component and a diol component. It should be understood that the foregoing details of polyurethane may also be applicable to manufacturing the polyurethane bend-elongated composite spoke joint assemblies of the second and fourth embodiments, and the joint assemblies used in the non-pneumatic tires of the third and fifth embodiments.

[0028] In general, according to the first to fifth embodiments disclosed herein, one or more diols may be used (or present in) the diol component of the polyurethane in the bend. The diol may be aromatic or aliphatic. In certain embodiments of the first to fifth embodiments, the diol component of the polyurethane in the bend is aromatic. In other preferred embodiments of the first to fifth embodiments, the diol component of the polyurethane in the bend is aliphatic. Generally, the diols used in the diol component of the polyurethane may vary, and suitable diols include diols having 2 to 20 carbon atoms (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 carbon atoms), preferably 2 to 10 carbon atoms, and more preferably 2 to 6 carbon atoms. According to the first to fifth embodiments, the diol component of the polyurethane in the bend can be selected from the group consisting of simple diols and composite polyols including polyester polyols, polyether polyols, polycarbonate polyols, polycaprolactone polyols, polybutadiene polyols, and polysulfide polyols. In certain embodiments of the first to fifth embodiments, the polyurethane in the bend includes a diol component selected from the group consisting of simple diols, polyester polyols, polyether polyols, polycarbonate polyols, polycaprolactone polyols, polybutadiene polyols, polysulfide polyols, and combinations thereof. Non-limiting examples of aliphatic diols include ethylene glycol, 1,4-butanediol, and 1,6-hexanediol, each of which can be understood as a simple diol. In certain embodiments of the first to fifth embodiments, the diol component of the polyurethane in the bend is selected from the group consisting of ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and combinations thereof. In certain embodiments of the first to fifth embodiments, the diol component of the polyurethane in the bent portion is ethylene glycol. In certain embodiments of the first to fifth embodiments, the diol component of the polyurethane in the bent portion is 1,4-butanediol.In a specific embodiment among the first to fifth embodiments, the diol component of the polyurethane in the bent portion consists of 1,6-hexanediol. Non-limiting examples of aromatic diols include those based on terephthalic acid, including diesters of terephthalic acid and diols having 2 to 4 carbon atoms.

[0029] In general, according to the first to fifth embodiments disclosed herein, one or more isocyanates may be used for (or present in) the isocyanate component of the polyurethane in the bent portion. The isocyanate may be aliphatic or aromatic. In a specific embodiment among the first to fifth embodiments, the isocyanate component of the polyurethane in the bent portion is aromatic or contains an aromatic isocyanate. In another embodiment among the first to fifth embodiments, the isocyanate component is aliphatic or contains an aliphatic isocyanate. In a specific embodiment among the first to fifth embodiments, the isocyanate component of the polyurethane is an aromatic diisocyanate selected from the group consisting of 4,4'-diphenylmethane diisocyanate (also known as methylene diphenyl diisocyanate), toluene diisocyanate, paraphenylene diisocyanate, and combinations thereof.

[0030] Examples of aliphatic isocyanates suitable for use as the isocyanate component of the polyurethane in the curved portion of the first to fifth embodiments include hexamethylene diisocyanate (HDI), ethylene diisocyanate, methylene dicyclohexyl diisocyanate (MDI), hydrogenated methylene dicyclohexyl diisocyanate (HMDI), or 4,4'-diisocyanatodicyclohexylmethane, isophorone diisocyanate (IPDI), or 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane, 1,6-diisocyanatohexane, and tetramethylxylylene diisocyanate. Examples include, but are not limited to, diisocyanates (TMXDI), alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene radical (e.g., 1,2-dodecane diisocyanate, 1,4-tetramethylene diisocyanate), 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, and combinations thereof. In certain embodiments of the first to fifth embodiments, the isocyanate component of the polyurethane is an aliphatic diisocyanate containing an aliphatic ether group.In certain embodiments of the first to fifth embodiments, the isocyanate component of the polyurethane in the bent portion is hexamethylene diisocyanate (HDI), methylene dicyclohexyl diisocyanate (MDI), hydrogenated methylene dicyclohexyl diisocyanate (HMDI), or 4,4'-diisocyanatodicyclohexylmethane, isophorone diisocyanate (IPDI), or 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane, 1,6-diisocyanatohexane, tetramethylxylylene The following are selected from the group consisting of diisocyanates (TMXDI), alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene radical (e.g., 1,2-dodecane diisocyanate, 1,4-tetramethylene diisocyanate), 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, and combinations thereof.

[0031] In certain embodiments of the first to fifth embodiments disclosed herein, the polyurethane in the bend portion comprises (and further comprises) at least one chain extender. In other embodiments of the first to fifth embodiments, the polyurethane in the bend portion does not contain a chain extender. In embodiments of the first to fifth embodiments in which the polyurethane in the bend portion comprises (and further comprises) at least one chain extender, the specific chain extender used may vary. In preferred embodiments of the first to fifth embodiments, the chain extender comprises a diol having 2 to 20 carbon atoms (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 carbon atoms), preferably 2 to 10 carbon atoms, and more preferably 2 to 6 carbon atoms. Generally, the chain extender may be either aliphatic or aromatic. In preferred embodiments of the first to fifth embodiments, any chain extender used is aliphatic. Non-limiting examples of aliphatic diols include ethylene glycol, 1,4-butanediol, and 1,6-hexanediol. In certain embodiments of the first to fifth embodiments, the chain extender for the polyurethane in the bend preferably comprises at least one aliphatic diol selected from the group consisting of ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and combinations thereof. In certain such embodiments, the chain extender for the polyurethane in the bend preferably comprises at least one aliphatic diol selected from the aforementioned group. Non-limiting examples of aromatic diols include terephthalic acid diesters and terephthalic acid-based diols having 2 to 4 carbon atoms. In certain embodiments of the first to fifth embodiments, the chain extender for the polyurethane in the bend comprises at least one aromatic diol. In certain such embodiments, the chain extender for the polyurethane in the bend comprises at least one aromatic diol.

[0032] The specific properties of the polyurethane bends in the first to fifth embodiments may vary. For example, in certain embodiments of the first to fifth embodiments, the polyurethane bends can function without cracking or fracturing at temperatures in the range of -65°F to 160°F (-55°C to 70°C).

[0033] Polyurethane bending section - slender composite spoke joint assembly According to the method of the first embodiment, the insert molding described above results in a polyurethane bend-to-elongated composite spoke joint in which the polyurethane bend is joined to the end of an elongated composite spoke that has been cured at least on its first surface. According to the second to fifth embodiments, the polyurethane bend-to-elongated composite spoke joint also includes a polyurethane bend joined to the end of an elongated composite spoke at least on its first surface. In certain embodiments of the first to fifth embodiments, the polyurethane bend is joined to the end of the elongated composite spoke at its first surface. In other embodiments of the first to fifth embodiments, the polyurethane bend is joined to the end of the elongated composite spoke at its first and second surfaces. In certain such embodiments, the polyurethane bend is joined to the entire outer surface of the (first) end of the elongated spoke (i.e., both the first and second surfaces, as well as any other surface between these two surfaces).

[0034] According to the method of the first embodiment, in the second to fifth embodiments, the polyurethane bend portion is at least 70 pli (e.g., 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, etc.), 70 to 250 pli, and at least 12000 N / m (e.g., 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000, 210 It is joined to the ends of the elongated composite spokes (i.e., at least on its first surface, as described above) with peel strengths of 0, 22000, 23000, 24000, 25000, 26000, 27000, 28000, 29000, 30000, 31000, 32000, 33000, 34000, 35000, 36000, 37000, 38000, 39000, 40000, 41000, 42000, 43000, 44000 N / m, etc., or 12000 to 44000 N / m. In preferred embodiments of the first to fifth embodiments, the peel strength is at least 90 pli (e.g., 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250 pli, etc.), 90 to 250 pli, and at least 16000 N / m (e.g., 16000, 17000, 18000, 19000, 18000, 19 (e.g., 000, 20000, 21000, 22000, 23000, 24000, 25000, 26000, 27000, 28000, 29000, 30000, 31000, 32000, 33000, 34000, 35000, 36000, 37000, 38000, 39000, 40000, 41000, 42000, 43000, 44000 N / m), or 16000-44000 N / m.In a more preferred embodiment among the first to fifth embodiments, the peel strength is at least 100 pli (e.g., 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250 pli, etc.), 70 to 250 pli, or at least 17000 N / m (e.g., 17000, 18000, 19000, 2000) The peel strengths are 0, 21000, 22000, 23000, 24000, 25000, 26000, 27000, 28000, 29000, 30000, 31000, 32000, 33000, 34000, 35000, 36000, 37000, 38000, 39000, 40000, 41000, 42000, 43000, 44000 N / m, etc., or 17000-44000 N / m. The aforementioned peel strengths can be measured at room temperature (i.e., 25°C) according to ASTM D6892 / D903.

[0035] The shape of the polyurethane bend obtained from insert molding and / or the polyurethane bend joined to the end of the elongated composite spoke as described above can vary. In certain embodiments of the first to fifth embodiments, the polyurethane bend has a shape selected from the group consisting of a rectangular parallelepiped; a curved hourglass; a polygon having an inner surface, an outer surface, and a peripheral edge between the inner and outer surfaces, wherein at least a portion of the peripheral edge is curved inward; and combinations thereof. As used herein, the phrase "curved inward" means a portion of the peripheral edge having a concave profile which can be selected from a variety of shapes including elliptical, partially circular, or irregular shapes. In certain embodiments of the first to fifth embodiments, the polyurethane bend has a rectangular parallelepiped shape. In certain embodiments of the first to fifth embodiments, the polyurethane bend has a curved hourglass shape. In certain embodiments of the first to fifth embodiments, the polyurethane bend has a polygonal shape having an inner surface, an outer surface, and a peripheral edge between the inner and outer surfaces, wherein at least a portion of the peripheral edge is curved inward. Similarly, a polyurethane bend resulting from insert molding may be understood as having two opposing surfaces, more specifically, a spoke-opposing surface (where the portion of the polyurethane bend in the polyurethane bend-to-elongated composite spoke joint is joined in contact with the spokes, as described above) and a band-opposing surface (where the polyurethane bend is joined in contact with the inner surface of the outer ring (also referred to herein as the annular ring) of a non-pneumatic tire). The joining or attachment between the polyurethane bend and the outer ring may be achieved using welding, brazing, soldering, adhesives, mechanical fasteners (e.g., bolts, rivets), key / keyway connections, or any other desired device. In embodiments of the first to fifth embodiments in which an adhesive is used to join the polyurethane bend to the outer ring, the specific adhesive used may vary. In certain embodiments of the first to fifth embodiments in which an epoxy adhesive is used to join the polyurethane bend to the outer ring.In other embodiments of the first to fifth embodiments, a hot-melt adhesive is used to bond the polyurethane bend to the outer ring.

[0036] hardening As described above, according to the method of the first embodiment disclosed herein, polishing is performed on the first surface of the cured elongated composite spoke. In other words, the polished elongated composite spoke is cured. Depending on the specific components used to prepare the composite spoke (e.g., the fibers and epoxy resin described above), various methods for curing the elongated composite spoke, including various temperatures, may be available.

[0037] The cured elongated composite spokes used in the method of the first embodiment and in the second to fifth embodiments disclosed herein can be cured using a variety of methods. In certain embodiments of the first to fifth embodiments, the elongated composite spokes (in their uncured state) are cured using heat and pressure to produce cured elongated composite spokes. The pressure used as part of such a curing process can vary. In certain embodiments of the first to fifth embodiments, curing is performed at 1 to 300 psig (e.g., 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, or 300 psig) or 7 to 2100 kPa (e.g., 7, 50, 100, 101, 200, 300, 400, 500, 600, 700, 800, 900) This includes applying pressure of 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, or 2100 kPa), preferably 5 to 100 psig (e.g., 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 psig) or 35 to 700 kPa (e.g., 35, 50, 100, 200, 300, 400, 500, 600, or 700 kPa). As used herein, psig refers to pounds per square inch in gauge units and kPa refers to kilopascals. The heat used as part of the curing process may vary.In certain embodiments of the first to fifth embodiments, curing occurs at 75-400°F (e.g., 75, 80, 85, 90, 95, 100, 110, 120, 125, 130, 140, 150, 160, 170, 175, 180, 190, 200, 210, 220, 225, 230, 240, 250, 260, 270, 275, 280, 290, 300, 310, 320°F). This includes heating at temperatures of 325, 330, 340, 350, 360, 370, 375, 380, 390, or 400°F, or 24 to 200°C (for example, 24, 25, 30, 40, 50, 60, 70, 75, 80, 90, 100, 110, 120, 125, 130, 140, 150, 160, 170, 175, 180, 190, or 200°C). In other embodiments of the first to fifth embodiments, curing includes heating at a temperature of 250 to 350°F (e.g., 250, 260, 270, 275, 280, 290, 300, 310, 320, 325, 330, 340, or 350°F) or 120 to 175°C (e.g., 120, 130, 140, 150, 160, 170, or 175°C). In certain embodiments of the first embodiment, curing includes the application of heat at one of the aforementioned temperatures and the application of pressure at one of the aforementioned values.

[0038] The fourth and fifth embodiments As described above, the fourth embodiment disclosed herein relates to a polyurethane bend-to-elongated composite spoke joint for use in non-pneumatic tires, the joint comprising a cured elongated composite spoke having an end having a first surface and a second surface, and composed of fibers selected from the group consisting of carbon fibers, glass fibers, aramid fibers and combinations thereof, and an epoxy resin, and a polyurethane bend joined to the end of the cured elongated composite spoke on its first surface with a peel strength of at least 70 pli (at least 12,000 N / m), preferably at least 90 pli (at least 16,000 N / m), more preferably 17,000 N / m and at least 100 pli, as determined by a 90-degree peel strength test (in accordance with ASTM D6892 / D903), wherein the end of the cured elongated composite spoke has a roughened surface on at least its first surface below the joined polyurethane bend. Furthermore, as described above, the fifth embodiment disclosed herein relates to a non-pneumatic tire incorporating the polyurethane bend-elongated composite spoke joint of the fourth embodiment. The following paragraphs specifically relate to the fourth and fifth embodiments disclosed herein and should not be understood as limiting the fourth and fifth embodiments to only the options discussed immediately below. Instead, the fourth and fifth embodiments should be understood as being broadly disclosed with respect to the fourth and fifth embodiments as described above, and as arising from the methods of the first to third embodiments as described above.

[0039] In certain embodiments of the fourth and fifth embodiments, the roughened surface has a roughness average Ra of 50 to 200 microinches (1.3 to 5 micrometers), preferably 70 to 170 microinches (2 to 4 micrometers), and more preferably 90 to 150 microinches (2.3 to 3.8 micrometers), as determined by profilometry.

[0040] In certain embodiments of the fourth and fifth embodiments, the roughened surface has an average maximum profile height Rz of 300 to 1000 microinches (8 to 25 micrometers), preferably 400 to 800 microinches (10 to 20 micrometers), and more preferably 500 to 700 microinches (13 to 18 micrometers), as determined by profilometry. In certain such embodiments, the average maximum profile height Rz is combined with the average roughness Ra value as described above.

[0041] In certain embodiments of the fourth and fifth embodiments, the epoxy resin of the elongated composite spoke has a curing time of 15 minutes or less at 150°C, preferably 12 minutes or less at 150°C.

[0042] In certain embodiments of the fourth and fifth embodiments, the first surface of the elongated composite spoke is flattened.

[0043] In certain embodiments of the fourth and fifth embodiments, the polyurethane bend portion has a shape selected from a rectangular parallelepiped; a curved hourglass; a polygon having an inner surface, an outer surface, and a peripheral edge between the inner and outer surfaces, wherein at least a portion of the peripheral edge is curved inward; and combinations thereof.

[0044] Non-pneumatic tire including polyurethane bend section - elongated composite spoke joint assembly As described above, the third embodiment disclosed herein relates to a non-pneumatic tire incorporating the polyurethane bend-elongated composite spoke joint of the second embodiment, which is manufactured by the method of the first embodiment. Also, as described above, the fifth embodiment disclosed herein relates to a non-pneumatic tire incorporating the polyurethane bend-elongated composite spoke joint of the fourth embodiment. Furthermore, an embodiment of the method of the first embodiment is disclosed herein, which further includes adding the polyurethane bend-elongated composite spoke joint to a non-pneumatic tire by joining the polyurethane bend-elongated composite spoke joint to an outer ring inside the non-pneumatic tire, wherein the outer ring has an outer surface and an inner surface, the outer surface being covered by the tread and the inner surface being joined to the polyurethane bend-elongated composite spoke joint via the polyurethane bend. A non-pneumatic tire of the fifth embodiment disclosed herein can be understood as including a polyurethane bend-elongated composite spoke joint of the fourth embodiment, the polyurethane bend-elongated composite spoke joint being joined to an outer ring within the non-pneumatic tire, the outer ring having an outer surface and an inner surface, the outer surface of which is covered by a tread and joined to the polyurethane bend-elongated composite spoke joint via a polyurethane bend.

[0045] This application discloses several numerical range limits that support any range within the disclosed numerical range, even if explicit range limits are not explicitly mentioned in the specification, because embodiments of the compositions and methods disclosed herein can be performed across the entire numerical range disclosed. With regard to the use of substantially any plural or singular term herein, those skilled in the art can substitute plurals for singulars or singulars for plurals as appropriate to the context or application. Various singular or plural substitutions may be explicitly described herein for brevity.

[0046] In general, those skilled in the art will understand that the terms used herein and in particular in the appended claims are generally intended to be “open” terms. For example, the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” and the term “listed” should be interpreted as “listed but not limited to.” Furthermore, those skilled in the art will understand that if a particular number is intended in the description of a preceding claim, such intention will be explicitly stated in that claim, and if there is no such statement, such intention does not exist. For example, to aid understanding, the following appended claims may include the use of the prefix phrases “at least one” and “one or more” to prefix the description of the claims. However, the use of such phrases should not be interpreted as meaning that the indefinite article "a" or "an" preamble to a claim is limited to an invention containing only one such claim, even if the same claim contains the preamble "one or more" or "at least one" and an indefinite article such as "a" or "an" (for example, "a" or "an" should typically be interpreted as meaning "at least one" or "one or more"), and the same applies to the use of definite articles used to preamble claims. In addition, even if a specific number is explicitly stated in the preamble of a claim, a person skilled in the art will understand that such a statement should typically be interpreted as meaning at least the number stated (for example, "two statements," which is an obvious statement without other modifiers, typically means at least two statements or two or more statements).Furthermore, when using conventional expressions similar to "at least one of A, B, and C, etc.," such expressions are generally intended to be understood by those skilled in the art (for example, "a system having at least one of A, B, and C" may include, but is not limited to, A only, B only, C only, A and B together, A and C together, B and C together, and / or a system having A, B, and C together). Furthermore, those skilled in the art will understand that any disjunct word or phrase that effectively indicates two or more alternative terms should be understood, whether in the specification, claims, or drawings, as intended to include the possibility of including one of these terms, any of these terms, or both of these terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."

[0047] All references, including but not limited to patents, patent applications, and non-patent literature, are incorporated herein by reference in their entirety.

[0048] While various aspects and embodiments of compositions and methods have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for illustrative purposes only and are not intended to limit the true scope and spirit set forth in the claims.

Claims

1. A method for manufacturing a polyurethane bend-to-slender composite spoke joint for use in non-pneumatic tires, To provide a cured, elongated composite spoke having an end with a first surface and a second surface, comprising a fiber selected from the group consisting of carbon fiber, glass fiber, aramid fiber, and combinations thereof, and an epoxy resin. To produce a roughened first surface, the first surface of the hardened elongated composite spoke is polished, Insert molding a polyurethane bend onto at least a portion of the roughened first surface of the hardened elongated composite spoke, A method comprising: producing a polyurethane bend-to-slender composite spoke joint having a peel strength of at least 70 pli (at least 12,000 N / m), preferably at least 90 pli (at least 16,000 N / m), and more preferably at 17,000 N / m, with a peel strength of at least 100 pli, as determined using a 90-degree peel strength test (in accordance with ASTM D6892 / D903).

2. The method according to claim 1, wherein the roughened first surface has an average roughness Ra of 50 to 200 microinches (1.3 to 5 micrometers), preferably 70 to 170 microinches (2 to 4 micrometers), more preferably 90 to 150 microinches (2.3 to 3.8 micrometers), as determined by profilometry.

3. The method according to claim 1 or 2, wherein the roughened first surface has an average maximum height Rz of a profile of 300 to 1000 microinches (8 to 25 micrometers), preferably 400 to 800 microinches (10 to 20 micrometers), more preferably 500 to 700 microinches (13 to 18 micrometers), as determined by profilometry.

4. The method according to any one of claims 1 to 3, wherein the polishing includes grit blasting.

5. The method according to any one of claims 1 to 3, wherein the polishing comprises using abrasive paper on the first surface of the hardened elongated composite spoke to produce the roughened first surface.

6. The method according to claim 4, wherein the grit blasting satisfies at least one, preferably each of the following: (a) using particles selected from the group consisting of aluminum oxide, alumina zirconia, silicon carbide, silica sand, garnet, steel, iron, quartz, walnut shells, and combinations thereof, preferably particles containing aluminum oxide; (b) using particles having a grit of 50 to 120 (330 to 120 microns); or (c) using a pressure of 30 to 80 psi (200 to 550 kPa), preferably 30 to 70 psi (200 to 500 kPa).

7. The method according to claim 5, wherein the abrasive paper satisfies at least one, preferably each of the following: (a) contains particles selected from the group consisting of aluminum oxide, alumina zirconia, silicon carbide, silica sand, garnet, steel, iron, quartz, walnut shell, and combinations thereof, or (b) has a grit of 50 to 120 (330 to 120 microns).

8. The method according to any one of claims 1 to 7, wherein the epoxy resin of the uncured elongated composite spoke has a curing time of 15 minutes or less at 150°C, preferably 12 minutes or less at 150°C.

9. The method according to any one of claims 1 to 8, wherein the first surface of the uncured elongated composite spoke is planarized.

10. The method according to any one of claims 1 to 9, wherein the polyurethane bend portion has a shape selected from the group consisting of a rectangular parallelepiped, a curved hourglass, an inner surface, an outer surface, and an outer peripheral edge between the inner surface and the outer surface, wherein at least a portion of the outer peripheral edge is curved inward, and combinations thereof.

11. Preferably, the method according to any one of claims 1 to 10, further comprising adding the polyurethane bend-slender composite spoke joint to the non-pneumatic tire by joining the polyurethane bend-slender composite spoke joint to the outer ring inside the non-pneumatic tire, wherein the outer ring has an outer surface and an inner surface, the outer surface being covered by a tread, and the inner surface being joined to the polyurethane bend-slender composite spoke joint via the polyurethane bend.

12. A polyurethane bend-to-slender composite spoke joint assembly manufactured by the method described in any one of claims 1 to 11.

13. A non-pneumatic tire incorporating the polyurethane bend-to-slip composite spoke joint described in claim 12.

14. A polyurethane bend-to-slender composite spoke joint assembly for use in non-pneumatic tires, A cured elongated composite spoke having an end with a first surface and a second surface, comprising a fiber selected from the group consisting of carbon fiber, glass fiber, aramid fiber, and combinations thereof, and an epoxy resin, A polyurethane bend is bonded to the end of the cured elongated composite spoke on its first surface, with a peel strength of at least 70 pli (at least 12,000 N / m), preferably at least 90 pli (at least 16,000 N / m), more preferably 17,000 N / m, and at least 100 pli, as determined by a 90-degree peel strength test (in accordance with ASTM D6892 / D903), A polyurethane bend-to-elongated composite spoke joint, wherein the end of the hardened elongated composite spoke has a roughened surface on at least its first surface below the joined polyurethane bend.

15. The polyurethane bend-to-slender composite spoke joint according to claim 14, wherein the roughened surface has an average roughness Ra of 50 to 200 microinches (1.3 to 5 micrometers), preferably 70 to 170 microinches (2 to 4 micrometers), more preferably 90 to 150 microinches (2.3 to 3.8 micrometers), as determined by profilometry.

16. The polyurethane bend-to-slender composite spoke joint according to claim 14 or 15, wherein the roughened surface has an average maximum height Rz of a profile of 300 to 1000 microinches (8 to 25 micrometers), preferably 400 to 800 microinches (10 to 20 micrometers), more preferably 500 to 700 microinches (13 to 18 micrometers), as determined by profilometry.

17. The polyurethane bent portion-elongated composite spoke joint according to any one of claims 14 to 16, wherein the epoxy resin of the elongated composite spoke has a curing time of 15 minutes or less at 150°C, preferably 12 minutes or less at 150°C.

18. The polyurethane bent portion-elongated composite spoke joint according to any one of claims 14 to 17, wherein the first surface of the elongated composite spoke is flattened.

19. The polyurethane bend portion has a shape selected from the group consisting of a rectangular parallelepiped, a curved hourglass, an inner surface, an outer surface, and an outer peripheral edge between the inner surface and the outer surface, wherein at least a portion of the outer peripheral edge is curved inward, and combinations thereof, as described in any one of claims 14 to 18.

20. A non-pneumatic tire incorporating a polyurethane bend-to-ellipse composite spoke joint according to any one of claims 14 to 19.

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