Shear band with ultra-low hysteresis rubber

Abstract

A shear band useful, for example, in a non-pneumatic tire is provided. The shear band uses staggered reinforcing elements positioned within a shear layer of elastomeric material. A variety of configurations may be used to create staggered positioning of the reinforcing elements, including, for example, a horizontal diamond configuration or a vertical diamond configuration. The shear layer is formed from a rubber composition having very low hysteresis reinforced with silica and carbon black and one or more anti-reversion chemicals selected from the group consisting of 1, 3-bis ((3-methyl-2, 5-dioxopyrrol-1-yl) methyl) benzene (CAS number: 119462-56-5) and hexamethylene 1, 6-bis (thiosulfuric acid) disodium salt dihydrate (CAS number: 5719-73-3).

Description

Background Art Technical Field

[0001] The present invention generally relates to a reinforced shear band useful in non-pneumatic tires and, more particularly, to a shear band comprising an ultra-low hysteresis rubber composition containing an anti-reversion agent and low surface area silica reinforcement.

[0002] Related technical description

[0003] Details and benefits of non-pneumatic tire constructions are described, for example, in U.S. Patent Nos. 6,769,465; 6,994,134; 7,013,939; and 7,201,194. Certain non-pneumatic tire constructions incorporate shear bands, embodiments of which are described, for example, in U.S. Patent Nos. 6,769,465 and 7,201,194, which are incorporated herein by reference. Such non-pneumatic tires offer advantages in tire performance without relying on gas inflation pressure to support the load applied to the tire.

[0004] As background, Figure 1 A cross-sectional view of an exemplary embodiment of a non-pneumatic tire 100 incorporating a shear band 110 is provided. Tire 100 also includes a plurality of tension-transmitting elements, shown as web spokes 150, which transversely span shear band 110 and extend inwardly from the shear band. Mounting bands 160 are positioned at the radially inner ends of the web spokes. Mounting bands 160 anchor tire 100 to hub 10. Tread portion 105 is formed around the periphery of shear band 110 and may include, for example, grooves or ribs thereon.

[0005] The shear band 110 of the tire 100 includes a shear layer and an innermost reinforcement layer adhered to the radially innermost extension of the shear layer and an outermost reinforcement layer adhered to the radially outermost extension of the shear layer. The tensile stiffness of the reinforcement layer is greater than the shear stiffness of the shear layer, so that the shear band undergoes shear deformation under a vertical load. More specifically, as described in U.S. Patent No. 7,201,194, when the elastic modulus of the reinforcement layer is equal to the shear modulus of the shear layer (E' 膜 When the ratio of G / G (as shown in U.S. Patent No. 7,201,194) is relatively low, the deformation of the shear band 110 under load approximates that of a uniform band and produces a non-uniform ground contact pressure. Alternatively, when this ratio is sufficiently high, the deformation of the shear band 110 under load is essentially shear deformation of the shear layer, with little longitudinal extension or compression of the reinforcement layer. Figure 1As indicated, a load L placed on the tire's axis of rotation X is transmitted to annular band 110 via tension in web spokes 150. Annular shear band 110 functions in a manner similar to an arch, providing sufficiently high circumferential compressive stiffness and longitudinal bending stiffness in the tire's equatorial plane to act as a load-bearing member. Under load, shear band 110 deforms in ground-contact area CA through a mechanism involving shear deformation of shear band 110. This ability to utilize shear deformation provides a flexible ground-contact area CA that functions similarly to a pneumatic tire, with similar advantageous results.

[0006] In addition to the embodiment shown in U.S. Patent No. 7,201,194, there are several non-pneumatic tire configurations that can incorporate shear bands. For example, U.S. Patent No. 6,769,465 relates to a structurally supported elastomeric tire that supports a load without internal air pressure. In an exemplary embodiment, this non-pneumatic tire includes a ground-contacting portion and a sidewall portion that extend radially inward from a tread portion and are anchored in a bead portion adapted to remain secured to the wheel during rolling. A reinforcing annular band is positioned radially inward of the tread portion. This shear band includes at least one uniform shear layer, a first membrane adhered to a radially inwardly extending portion of the shear layer, and a second membrane adhered to a radially outwardly extending portion of the shear layer. Each of the membranes has a longitudinal tensile modulus sufficiently greater than the dynamic shear modulus of the shear layer such that, when under load, the ground-contacting portion of the tire deforms into a flat contact patch due to shear strain in the shear layer while maintaining a constant length of the membrane. Relative displacement of the membranes occurs primarily due to shear strain in the shear layer. The invention of US Patent No. 6,769,465 offers several advantages, including, for example, the ability to operate without inflation pressure and the flexibility to adjust the vertical stiffness of the tire somewhat independently of ground contact pressure.

[0007] In the case of both pneumatic and non-pneumatic tires, there is a need to improve the fuel efficiency of tires. Such improvements can be achieved, for example, by reducing the overall size or mass of the tire and / or using lower-loss materials in the tire. For non-pneumatic tires that utilize shear bands with uniform shear layers, such reductions can be challenging. For example, because the shear modulus of these materials is typically low, using shear layer materials with low energy dissipation can result in an unacceptable increase in the required material mass.

[0008] An example of such an improvement is the invention disclosed in International Application PCT / US1166793, filed December 22, 2011, which discloses a shear band having discrete reinforcing elements positioned throughout the annular shear layer.

[0009] Therefore, a shear band that can improve fuel efficiency by, for example, reducing mass and / or rolling resistance and / or improving the material from which the shear band is formed would be beneficial. Such a shear band that can be incorporated into a variety of non-pneumatic tire constructions would be particularly useful. Summary of the Invention

[0010] Certain embodiments of the present invention include an annular shear band and an article having an annular shear band, including a non-pneumatic tire. Such annular shear band may include an annular shear layer comprised of a rubber composition and a plurality of discrete annular reinforcing elements positioned throughout the annular shear layer along a plurality of axially oriented rows. The reinforcing elements may be separated from one another by a predetermined distance, each reinforcing element having a center point, wherein the reinforcing elements are staggered along an axial direction or a radial direction of the shear band such that the center points of the reinforcing elements of adjacent axially oriented rows are arranged to form a rhombus having non-orthogonal angles between the sides of the rhombus.

[0011] The rubber composition of the annular shear layer is based on a crosslinkable rubber composition comprising, in parts by weight per 100 parts by weight of rubber (phr), between 50 and 100 phr of natural rubber and between 0 and 50 phr of a second rubber component and at least one anti-reversion chemical selected from the group consisting of hexamethylene 1,6-bis(thiosulfate) disodium salt dihydrate ("HTSNA") or 1,3-bis((3-methyl-2,5-dioxopyrrol-1-yl)methyl)benzene ("D900"). The second rubber component may be selected from the group consisting of polybutadiene rubber, copolymers of polybutadiene and styrene, and combinations thereof, wherein the copolymer has no more than 5 mole percent styrene.

[0012] In at least one embodiment, the rubber composition of the annular shear layer is based on a crosslinkable rubber composition comprising, in parts by weight per 100 parts by weight of rubber (phr), between 50 and 100 phr of natural rubber and between 0 and 50 phr of a second rubber component and between 0.5 and 2.5 phr of the anti-reversion chemical hexamethylene 1,6-bis(thiosulfate) disodium salt dihydrate ("HTSNA"). The second rubber component may be selected from the group consisting of polybutadiene rubber, copolymers of polybutadiene and styrene, and combinations thereof, wherein the copolymer has no more than 5 mole percent styrene.

[0013] In another embodiment having the composition as described above in the preceding paragraph, wherein the anti-reversion chemical HTSNA is present in the range of 1.0 phr to 2.5 phr.

[0014] In at least one embodiment, the rubber composition of the annular shear layer is based on a crosslinkable rubber composition comprising, in parts by weight per 100 parts by weight of rubber (phr), between 50 and 100 phr of natural rubber and between 0 and 50 phr of a second rubber component and between 0.46 and 2.28 phr of the anti-reversion chemical 1,3-bis((3-methyl-2,5-dioxopyrrol-1-yl)methyl)benzene ("D900"). The second rubber component may be selected from the group consisting of polybutadiene rubber, copolymers of polybutadiene and styrene, and combinations thereof, wherein the copolymer has no more than 5 mole percent styrene.

[0015] In another embodiment having a composition as described above in the preceding paragraphs, wherein the anti-reversion chemical D900 is present in the range of 0.91 phr to 1.83 phr.

[0016] Such rubber compositions as described above may also contain between 25 and 60 phr of reinforcing filler, the reinforcing filler being limited to a first portion being between 35 and 70 weight percent of the total silica and having a ratio of 40 m 2 / g and 55m 2 The second part is carbon black between 30% and 65% by weight of the total amount of reinforcing filler and has a surface area between 15m 2 / g and 45m 2 Target surface area between 1000 and 1000 g. Also includes sulfur cure system.

[0017] The rubber compositions disclosed herein may include physical properties having low hysteresis. Accordingly, certain embodiments of the rubber compositions disclosed herein have a tan delta between 0.015 and 0.025, measured at 23°C and 50% strain.

[0018] The foregoing and other objects, features, and advantages of the invention will be apparent from the following more detailed description of specific embodiments of the invention as illustrated in the accompanying drawings wherein like reference numerals represent like parts of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic side view of an exemplary embodiment of a tire incorporating a shear band is provided.

[0020] Figure 2 A perspective view of an exemplary embodiment of a tire incorporating the shear strip of the present invention is provided.

[0021] Figure 3 Provided along Figure 2 The line 3-3 in the Figure 2 Cross-section of a tire.

[0022] Figure 4 It can be used with Figure 1 and Figure 2 A cross-sectional view (along the direction of the shear band) of a portion of an exemplary embodiment of a non-pneumatic tire is shown. Figure 2 3-3).

[0023] Figure 5 It can be used for example Figure 4 Schematic illustration of exemplary positioning (eg, staggering) of reinforcing elements of the present invention in a shear band.

[0024] Figure 6 and Figure 7 A schematic illustration of non-interlaced reinforcement elements is provided.

[0025] Figure 8 It can be used with Figure 1 and Figure 2 A cross-sectional view of a portion of an exemplary embodiment of a shear band for use with a non-pneumatic tire is shown.

[0026] Figure 9 It can be used for example Figure 8 Schematic illustration of exemplary positioning (eg, staggering) of reinforcing elements of the present invention in a shear band. DETAILED DESCRIPTION

[0027] Embodiments of the present invention include a shear band that can be used in non-pneumatic tires, and more specifically, relate to rubber compositions that form the shear layer of an annular shear band. As mentioned above, the shear band concept has been used in many different embodiments of non-pneumatic tires and is well known in the industry. The improvements to the shear bands provided herein provide significantly improved rolling resistance and, therefore, improved fuel economy when included in a non-pneumatic tire. It should be noted that non-pneumatic tires include tires that are designed to be run-flat tires, i.e., tires that are designed to travel a distance after losing inflation pressure. Shear bands having a staggered arrangement of reinforcing elements positioned in the annular shear layer thereof are known, and are described in International Patent Application PCT / US1166793, filed December 22, 2011.

[0028] The inventors have determined that the shear bands disclosed herein operate under high strain conditions, such as greater than 70% strain or even greater than 80%. These shear bands comprise an annular shear layer having a plurality of discrete annular reinforcement elements positioned throughout the annular shear layer along a plurality of axially oriented rows, as described in greater detail below. The reinforcement elements of the shear band support the load, and the annular shear layer, made of an elastic material, primarily serves to hold the reinforcements in place. Furthermore, as a result of the design, the reinforcement architecture exhibits extremely low strain energy release, resulting in a slow crack growth rate.

[0029] This is significant in that the materials that can be used for the annular shear layer of the shear band can be materials not currently found in tires. In other words, the materials can exhibit low hysteresis at high strain amplitudes, such as greater than 70% strain or greater than 80% strain, but are not particularly associated with the low crack growth rate or viscous and tearing properties of such elastomeric materials.

[0030] Thus, a particular embodiment of the shear layer disclosed herein is a rubber composition comprising, prior to vulcanization, between 50 and 100 phr of natural rubber and between 0 and 50 phr of a second rubber component, which second rubber component can be selected from, for example, polybutadiene rubber, a copolymer of polybutadiene rubber and styrene (but not more than 5 mole % of styrene), or a combination of such rubber components, and one or more anti-reversion chemicals selected from 1,3-bis((3-methyl-2,5-dioxopyrrol-1-yl)methyl)benzene (CAS No. 119462-56-5) and hexamethylene 1,6-bis(thiosulfate) disodium salt dihydrate (CAS No. 5719-73-3).

[0031] Additionally, certain embodiments are reinforced with low levels of reinforcing fillers, such as between 20 and 50 phr, with a surface area of ​​15 m 2 / g and 45m 2 The carbon black content may not exceed 35 phr between 100 and 1000 Å / g. This keeps the hysteresis of the material at ultra-low levels, but includes sufficient reinforcement to provide cohesion and strain-at-break properties that may be preferred for different embodiments.

[0032] As mentioned above, the shear bands disclosed herein use staggered reinforcing elements positioned within a shear layer of an elastic material. A variety of configurations can be used to produce the staggered positioning of the reinforcing elements. For the purpose of describing the present invention, reference will now be made in detail to embodiments and / or methods of the present invention, one or more examples of which are shown in or with the accompanying drawings. Each example is provided as an explanation of the present invention and not as a limitation of the present invention. Indeed, it will be clear to those skilled in the art that various modifications and changes can be made in the present invention without departing from the scope or spirit of the present invention. For example, features or steps illustrated or described as part of one embodiment can be used together with another embodiment or step to produce yet another embodiment or method. Therefore, it is intended that the present invention covers such modifications and variations as if they were within the scope of the appended claims and their equivalents.

[0033] For purposes of this disclosure, the following terms are defined as follows:

[0034] "Axial direction" or the letter "A" in the figures refers to a direction parallel to the axis of rotation of, for example, a shear belt, tire, and / or wheel as it travels along a road surface.

[0035] A "radial direction" or the letter "R" in the drawings refers to a direction that is normal to the axial direction and extends in the same direction as any radius extending normal to the axial direction.

[0036] "Equatorial plane" means a plane passing perpendicular to the axis of rotation and bisecting the shear band and / or wheel structure.

[0037] "Staggered" refers to the manner in which the discrete reinforcements or reinforcing elements of a shear band are arranged within the shear layer, as will be further described with reference to the accompanying drawings. When the reinforcing elements are staggered along the axial direction, an imaginary line extending between the center points of the reinforcing elements in adjacent axially oriented rows will form a rhombus or horizontal diamond with non-orthogonal angles between the sides of the rhombus. In this staggered horizontal diamond configuration, the reinforcing elements in adjacent axially oriented rows are closer together than the reinforcing elements in the same axially oriented row. When the reinforcing elements are staggered along the radial direction, an imaginary line extending between the center points of the reinforcing elements in adjacent axially oriented rows will form a rhombus or vertical diamond with non-orthogonal angles between the sides of the rhombus. In this staggered vertical diamond configuration, the reinforcing elements in the same axially oriented row are closer together than the reinforcing elements in non-adjacent axially oriented rows. As will be understood by those skilled in the art using the teachings disclosed herein, during tire manufacturing, the reinforcing elements may not be perfectly positioned into the shape of a vertical or horizontal diamond due to, for example, movement of the material during the manufacturing process. Thus, the reinforcing elements of the diamond configuration may be slightly displaced.

[0038] As used herein, "phr" means "parts per hundred parts by weight of rubber" and is a common measurement in the art where a component of a rubber composition is measured relative to the total weight of rubber in the composition, i.e., parts by weight of the component per 100 parts by weight of total rubber in the composition.

[0039] As used herein, "based on" is a term that recognizes that embodiments of the present invention are made from a vulcanized rubber composition or cured rubber composition that is uncured at the time of assembly. Thus, the cured rubber composition is "based on" the uncured rubber composition. In other words, the crosslinked rubber composition is based on or includes ingredients of a crosslinkable rubber composition.

[0040] Exemplary Non-Pneumatic Tire Architecture . Figure 2 An exemplary embodiment of a non-pneumatic tire 201 that may incorporate the shear bands of the present invention is provided. Figure 3 Provided along Figure 2 A cross-sectional view of the tire 201 taken along line 3-3 in FIG. Figure 2 and Figure 3 The tire 201 is shown having an annular shear band 205 and a plurality of tension transmitting elements, shown as web spokes 220, which span the band 205 transversely and extend inwardly from the band to a mounting band 225 at the radially inner end of the web spokes 220. The mounting band 225 anchors the tire 201 to the hub 230 for mounting using holes 235. The tire 201 can be mounted to the hub 230 or can be integrally constructed with the hub 230.

[0041] The tread portion 210 is formed at the outer periphery of the belt 205. The tread portion 210 may be joined to the Figure 2 The additional rubber layer on the belt 205 shown may be, for example, to provide traction and wear properties different from the material used to construct the belt 205. Alternatively, the tread portion 210 may be formed as part of the outer surface of the flexible belt 205. In yet another alternative, the belt 205 may be enclosed within one or more rubber materials that are connected to the tread portion 210. Tread features may be formed in the tread portion 210 and may include, for example, blocks 215 and grooves 240.

[0042] As mentioned, Figure 2 and Figure 3 The web spokes 220 in the exemplary embodiment of extend transversely across the wheel 201, which, as used herein, means that the web spokes 220 extend from one side of the wheel 201 to the other and may be aligned with the axis of rotation, or may be tilted relative to the axle. Additionally, "extending inwardly" means that the web spokes 220 extend between the band 205 and the mounting band 225 and may be in a plane radial to the axle or may be tilted relative to the radial plane. Additionally, as Figure 2As shown, the web spokes 220 may actually include spokes at various angles to the radial plane. Various shapes and patterns may be used, for example, as shown in U.S. Patent No. 7,013,939 and WO 2008 / 118983. Therefore, as will be appreciated by one of ordinary skill in the art, the present invention is not limited to the radial spokes shown in the figures, as other shapes and orientations, as well as a different number of web spokes than shown, may be used.

[0043] The annular shear band 205 supports the load on the wheel 201 and elastically deforms to conform to the road (or other supporting surface), thereby providing traction, comfort, and handling. More specifically, as described in U.S. Patent No. 7,013,939, when a load L is placed on the wheel 201 through the hub 230, the band 205 acts compliantly because it bends and otherwise deforms to make ground contact (the present application). Figure 3 The belt 205 is a wheel that is not in contact with the ground and forms the contact surface, which is the portion of the wheel 201 that is in contact with the ground under such a load. The portion of the belt 205 that is not in contact with the ground acts in a manner similar to an arch and provides sufficiently high circumferential compressive stiffness and longitudinal bending stiffness in the equatorial plane to act as a load-bearing member.

[0044] The load on the wheel 201 transferred from the vehicle (not shown) to the hub 230 is essentially carried out by the load-bearing portion attached to the belt 205 (by Figure 1 The web spokes 220 are suspended (e.g., as indicated by arrows K in FIG. Figure 3 (The tensile force is shown by arrow T). Due to the load, the web spokes 220 in the ground contact area do not experience tensile loads, and, for example, in certain exemplary embodiments, the spokes 220 may deform or even compress above the ground contact area under load. Of course, as the wheel 201 rotates, the specific portion of the flexible band 205 that acts as an arch constantly changes; however, the concept of an arch is useful in understanding the load-supporting mechanism. The amount of flexure of the band 205, and therefore the size of the contact patch, is proportional to the load. The ability of the band 205 to elastically flex under load provides a flexible ground contact area that functions similarly to the ground contact area of ​​a pneumatic tire, with similar advantageous results.

[0045] Still refer to Figure 2 and Figure 3, the web spokes 220 are essentially sheet-like elements having a length H in the radial direction and a width W in the axial direction that generally corresponds to the axial width of the flexible strip 205, but other widths W may be used, including widths W that vary along the radial direction. The web spokes 220 also have a thickness (i.e., a dimension perpendicular to the length H and width W) that is generally much smaller than the length H or width W, which allows the web spokes to deform or bend under compression. Thinner web spokes will bend as they pass through the contact area with essentially no compression resistance, that is, they will not supply any or only a negligible compression force to the load-bearing member. As the thickness of the web spokes 220 increases, the web spokes can provide some compressive load bearing capacity in the ground contact area. However, the dominant load transferring action of the entire web spoke 220 is in tension ( Figure 3 The specific web spoke thickness K can be selected to meet the specific requirements of the vehicle or application.

[0046] like Figure 2 and Figure 3 As seen in FIG, the web spokes 220 are preferably oriented relative to the flexible band 205 across the axial direction A. Thus, tension in the web spokes 220 is distributed across the band 205 to support the load. By way of example, the web spokes 220 can be formed from an elastic material having a tensile modulus of approximately 10 MPa to 100 MPa. If desired, the web spokes 220 can be reinforced and can support compressive loads, such as those taught in U.S. Patent Application Publication Nos. US2020 / 0039293 and US2019 / 0337329.

[0047] for Figure 2 and Figure 3 In the exemplary embodiment of the present invention, the web spokes 220 are interconnected by a radially inner mounting band 225 that surrounds the hub 230 to mount the tire 201 to the hub 230. Depending on the materials of construction and the manufacturing process, the hub 230, mounting band 225, annular band 205, and web spokes 220 may be molded as a single unit. Alternatively, one or more of these components may be formed separately and then attached to each other by, for example, adhesives or molding. In addition, other components may also be included. For example, an interface band may be used to connect the web spokes 220 at their radially outer ends, and the interface band will then be connected to the band 205.

[0048] According to another embodiment, the web spokes 220 can be mechanically attached to the hub 230, for example, by providing an enlarged portion on the inner end of each web spoke 220 that engages a slot in the hub 230, or by attaching adjacent web spokes 220 to form loops at hooks or posts formed in the hub 230. Substantially complete tensile load support is achieved by having web spokes 220 with high effective tensile stiffness but very low compressive stiffness. To facilitate bending in a particular direction, the web spokes 220 can be curved. Alternatively, the web spokes 220 can be molded with a curvature and can be straightened during cooling by heat shrinkage to provide a tendency to bend in a particular direction.

[0049] The web spokes 220 should resist twisting between the annular band 205 and the hub 230, for example, when torque is applied to the wheel 201. Additionally, the web spokes 220 should resist lateral deflection, for example, during rotation or slewing. As will be appreciated, web spokes 220 that are in the radial-axial plane, i.e., aligned with both the radial and axial directions, will have high resistance to axial gravitational forces, but specifically, if elongated in the radial direction R, the web spokes can have relatively low torque resistance in the circumferential direction C.

[0050] For certain vehicles and applications, such as those producing relatively low torque, a web spoke package having relatively short spokes 220 aligned with the radial direction R would be appropriate. For applications where high torque is expected, such as that of U.S. Patent 7,013,939 Figures 5 to 8 One of the arrangements shown may be more suitable. In the variation shown therein, an orientation of the web spokes is provided that includes resistance components in both the radial and circumferential directions, thereby increasing resistance to torque while maintaining radial and lateral resistance components. The angle of orientation can be selected based on the number of web spokes used and the spacing between adjacent web spokes. Other alternative arrangements may also be used.

[0051] It should be understood that the present invention is not limited to Figure 2 The tire 201 shown, and alternatively, may take a variety of configurations. For example, the tire 201 may be constructed with a shear band incorporated into the rubber layer such that, for example, the sidewalls overlie the axially outermost portions of the shear band.

[0052] shear zone .like Figure 4 As more particularly shown in the partial cross-sectional view of FIG, annular shear band 205 includes a plurality of discrete reinforcing elements 250 positioned within an annular shear layer 255 comprised of an elastomeric material. Reinforcing elements 250 are positioned along axially oriented rows such as, for example, rows 260, 265, and 270. Figure 4 In the exemplary embodiment of FIG. 2 , the reinforcing elements 250 are staggered along the radial direction R.

[0053] More specifically, now refer to Figure 5 In the schematic illustration shown, the reinforcing elements 250 are arranged such that an imaginary line L (shown in dashed lines) extending between the center points of the reinforcing elements 250 located in adjacent axially-oriented rows 260, 265, and 270 will form a rhombus or perpendicular diamond 251 having an obtuse angle α between some of the sides L of the rhombus. Additionally, the reinforcing elements 250 along the same axially-oriented row (such as the reinforcing elements in row 265) will be closer together than the reinforcing elements in non-adjacent axially-oriented rows (such as the reinforcing elements in row 260 relative to row 270).

[0054] For clarity, Figure 6 and Figure 7 The positioning of the reinforcing elements 250 is shown which is not "staggered" within the meaning of this application. Figure 6 and Figure 7 In the examples, the centers of the reinforcing elements 250 are located along the rhombus 252 or 253, respectively. However, the angle α as used in these examples is 90 degrees, and the reinforcing elements 250 are all equally spaced, whether along the same or different axially oriented rows 275, 280, and 285.

[0055] Figure 8 A partial cross-sectional view of another exemplary embodiment of a shear band 205 is provided. Again, the annular shear band 205 includes a plurality of discrete reinforcing elements 250 positioned within an annular shear layer 255 comprised of an elastomeric material. The reinforcing elements 250 are positioned along axially oriented rows such as, for example, rows 290, 295, 300, 305, and 310. Figure 8 In the exemplary embodiment of FIG. 2 , the reinforcing elements 250 are staggered along the axial direction A.

[0056] More specifically, now refer to Figure 9 In the schematic illustration shown, the reinforcing elements 250 are arranged such that an imaginary line L (shown in dashed lines) extending between the center points of the reinforcing elements 250 located in adjacent axially-oriented rows 290, 295, 300, 305, and 310 will form a rhombus or horizontal diamond 254 having acute angles α between certain sides L of the rhombus 254. Additionally, the reinforcing elements 250 along adjacent axially-oriented rows (such as the reinforcing elements in row 290 relative to row 295 or in row 295 relative to row 300) will be closer together than the reinforcing elements positioned along the same axially-oriented row (e.g., such as the reinforcing elements 250 in row 290 or row 295).

[0057] Return to Figure 4 and Figure 52. The reinforcing elements 250 are arranged in a staggered, vertical diamond configuration, each having a nominal diameter Φ as shown. In certain exemplary embodiments of the present invention, the spacing ws between the reinforcing elements 250 positioned along an axially-oriented row (such as, for example, row 265) is in the range of about Φ / 2 to about Φ / 10, or about Φ / 4. Additionally, in certain exemplary embodiments of the present invention, the spacing between the reinforcing elements 250 positioned in adjacent axially-oriented rows (such as, for example, rows 260 and 265 or rows 265 and 270) is in the range of about Φ / 2 to about Φ / 10, or about Φ / 4.

[0058] Return to Figure 8 and Figure 9 290 and 295, or rows 295 and 300, are arranged in a staggered horizontal diamond configuration, each of the reinforcing elements 250 also having a nominal diameter Φ as shown. The reinforcing elements 250 are separated from each other by a predetermined distance ws. In certain exemplary embodiments of the present invention, the spacing ws between the reinforcing elements 250 positioned in adjacent axially oriented rows (such as, for example, rows 290 and 295 or rows 295 and 300) ranges from about Φ / 2 to about Φ / 10, or is about Φ / 4. Additionally, in certain exemplary embodiments of the present invention, the spacing between the reinforcing elements 250 positioned in non-adjacent axially oriented rows (such as, for example, rows 290 and 300 or rows 295 and 305) ranges from about Φ / 2 to about Φ / 10, or is about Φ / 4.

[0059] The reinforcing element 250 can be made of a variety of materials. For example, the reinforcing element 255 can be made of a metal cable or a cable made of polymer monofilaments such as PET (polyethylene terephthalate) or nylon. As an additional example, the reinforcing element 250 can be made of a slender composite element with a monofilament appearance. The composite element is made of substantially symmetrical technical fibers, which have a long length and are impregnated in a thermosetting resin with an initial elongation modulus of at least 2.3 GPa, wherein the fibers are all parallel to each other. In this embodiment, the slender composite element will deform elastically until it reaches a compressive strain of at least 2%. As used herein, elastic deformation means that when the stress is released, the material will roughly return to its original state. When the slender composite element is deformed in bending, its compressive fracture stress will be greater than the extension fracture stress, all of which are described in, for example, U.S. Patent No. 7,032,637, which is incorporated herein by reference. As an example, the fiber can be made of glass, certain carbon fibers with a low Young's modulus, and combinations thereof. Preferably, the thermosetting resin has a glass transition temperature T greater than 130°C. g Advantageously, the thermosetting resin has an initial elongation modulus of at least 3 GPa. The reinforcing element 250 may also consist of a combination of PET and such elongated composite elements.

[0060] Alternatively, the reinforcing element 255 may be formed from a hollow tube made from a rigid polymer such as, for example, PET or nylon. Other materials may also be used. In certain exemplary embodiments of the present invention, preferably, each of the reinforcing elements 250 has a nominal diameter φ in the range of about ND / 200 to about ND / 1000, where ND is the nominal diameter of the shear band 205 (see Figure 3 ).

[0061] Shear layer As mentioned above, the shear bands disclosed herein operate in a high strain regime, and it has been determined that the choice of material used in the shear layer has a significant impact on rolling resistance. Since the material is not load-bearing, and due to the design of the shear layer, crack growth resistance is not particularly important, different material properties, and therefore different materials, that are not typically used in tires can be considered.

[0062] The shear bands and shear layers of the embodiments disclosed herein may be used in many different non-pneumatic tire arrangements, and the description of examples of non-pneumatic tires having shear bands as described above is not intended to limit the designs of non-pneumatic tires that would benefit from the use of the shear bands disclosed herein.

[0063] Since shear bands operate under high strain, it is preferred that the hysteresis at high strains be as low as possible so that rolling resistance can be reduced. Since the shear layer does not provide support but primarily holds the reinforcement in place, crack growth resistance, tear properties, and cohesion are not as important as they are typically in tires, and therefore those properties can be relaxed to provide the lowest possible hysteresis for the rubber composition.

[0064] A preferred material for the shear layer is a rubber composition. Specific embodiments of the rubber compositions suitable for shear layers disclosed herein comprise a diene rubber that is at least partially derived from a conjugated diene monomer content greater than 50 mol %. Such diene elastomers suitable for shear layers include, for example, natural rubber (NR), polybutadiene rubber (BR), and copolymers of polybutadiene rubber and styrene (SBR). The use of these diene rubbers is particularly useful for obtaining the ultra-low hysteresis required for the shear layer. For specific embodiments, the SBR copolymer is limited to having no more than 5 mol % bound styrene, as higher amounts may undesirably increase the hysteresis of the rubber composition. However, when the SBR is functionalized with a moiety that can interact with the silica reinforcing filler, the bound styrene content can be higher, for example, between 1 mol % and 35 mol %, or alternatively between 1 mol % and 30 mol %, or between 1 mol % and 20 mol % bound styrene content. In specific embodiments, higher bound styrene contents, i.e., greater than 30 mol %, are not applicable. Functionalized rubbers, i.e., those having attached reactive moieties, are well known in the industry, and such rubbers can be functionalized by attaching these reactive moieties to the polymer backbone along the branches of the polymer or at the ends of the branches of the polymer. Suitable functionalized moieties that interact with silica fillers include, for example, silanol groups, polysiloxane groups, alkoxysilane groups, and amino groups.

[0065] At least for some of the embodiments disclosed herein, the rubbers can have any microstructure, such microstructure varying with the polymerization conditions used, in particular the presence or absence of modifiers and / or randomizers and the amount of modifiers and / or randomizers used. The elastomers can be, for example, block, random, sequential, or microsequential elastomers and can be prepared in dispersion or solution; they can be coupled and / or star-shaped or alternatively functionalized by coupling and / or star-shaped or functionalizing agents.

[0066] As mentioned above for functionalized SBR, functionalized rubbers, i.e., those having reactive moieties attached, are well known in the industry. The main or side chain ends of the elastomer can be functionalized by attaching these reactive moieties to the ends of the chain or to the main or mid-chain of the polymer. Any of the rubbers used in the rubber compositions disclosed herein may optionally contain a functional moiety. Exemplary functionalizing agents that may be included with the diene elastomer include, but are not limited to, metal halides, metalloid halides, alkoxysilanes, imine-containing compounds, esters, ester-carboxylic acid metal complexes, alkyl ester carboxylic acid metal complexes, aldehydes or ketones, amides, isocyanates, isothiocyanates, and imines, all of which are well known in the art. Specific embodiments may include a functionalized diene elastomer, while other embodiments may be limited to not including a functionalized elastomer.

[0067] The specific embodiment of the rubber composition disclosed herein may be included in a natural rubber between 50phr and 100phr, or alternatively between 60phr and 100phr, between 75phr and 100phr, between 85phr and 100phr, between 50phr and 90phr or between 60phr and 90phr.Specific embodiments may be limited to the natural rubber of 100phr.Other embodiments may be limited to the natural rubber of 90phr.If less natural rubber is included, the target ultra-low hysteresis of the cured rubber composition may not be achieved.If a larger amount of polybutadiene is included, the cohesive properties of the rubber composition are not suitable, that is, the fracture strain is not large enough compared to the strain state of shear layer operation.

[0068] In addition to natural rubber, the rubber composition may also include a second rubber component between 0 phr and 50 phr, the second rubber component being selected from the group including polybutadiene rubber and styrene-butadiene copolymer or a combination thereof, the content of bound styrene of the styrene-butadiene copolymer not exceeding 5 mol % or alternatively not exceeding 3 mol %. Specific embodiments may be limited to a second rubber component of 0 phr or alternatively an SBR copolymer of 0 phr. Specific embodiments may be limited to natural rubber and a second rubber component; that is, the rubber component of the rubber composition disclosed herein includes natural rubber, and the remainder is a second rubber component. Including only these rubber components can help ensure that the disclosed rubber composition can achieve ultra-low hysteresis targets. As described above, when SBR is functionalized with a portion that interacts with a silica-reinforced filler, the embodiments of the rubber composition disclosed herein that is at least partially reinforced with a silica filler may further include a functionalized SBR component between 0 phr and 20 phr, or alternatively a functionalized SBR between 0 phr and 15 phr or between 0 phr and 10 phr. In certain embodiments, the amount of such functionalized SBR is limited to 0 phr.

[0069] In addition to the rubber component, the rubber composition disclosed herein also includes a reinforcing filler. The reinforcing filler is added to the rubber composition to improve, in particular, its tensile strength and its stiffness. Reinforcing fillers well known in the industry include, for example, carbon black and silica.

[0070] The carbon blacks that can be used in the rubber compositions disclosed herein are very limited because other carbon blacks may not be able to provide the ultra-low hysteresis properties that are targeted along with other desired properties. In certain embodiments, the carbon blacks are limited to those with a target surface area of ​​15 m 2 / g and 45m 2 / g or alternatively between 32m 2 / g and 39m 2 / g, as measured according to ASTM D6556. According to ASTM D1765 standard classification of carbon blacks, the surface area is between 15m 2 / g and 32m 2 Those carbon blacks with a mass between 100 and 200 sq. m / g are classified as Group 7 and have a surface area between 33 m 2 / g and 39m 2 Those carbon blacks with surface areas between 0.01 and 0.06 g / g are classified as Group 6. Examples of such Group 6 carbon blacks include N630, N650, N660, N683, and examples of such Group 7 carbon blacks include N754, N762, N765, N772, and N787. Small amounts of carbon black outside these desired ranges may be included in certain embodiments, but in other embodiments, carbon blacks with surface areas outside these target surface area ranges would be unacceptable.

[0071] Silica is another suitable reinforcing filler and is an inorganic filler. Silica can take a variety of suitable forms, including, for example, powder, microbeads, granules, spheres, and / or any other suitable form, and mixtures thereof. Such silica can be fumed, precipitated, and / or highly dispersible silica (referred to as "HD" silica).

[0072] Useful silicas for particular embodiments of the rubber compositions disclosed herein comprise silicas with a surface area of ​​40 m 2 / g and 55m 2 / g or alternatively between 40m 2 / g and 47m 2 / g or between 41m 2 / g and 45m 2 / g of silica. Examples of useful silicas may include, for example, EXP7031-1, which is available from Evonik. The surface area of ​​the silica filler is determined according to ASTM D1993. These suitable silicas are typically in powder form.

[0073] To achieve the desired physical properties of the rubber composition, the loading of reinforcing filler is low. If the loading becomes too high, the ultra-low hysteresis goal cannot be achieved, and if the loading is too low, the reinforcement of the rubber composition is insufficient to hold it together and keep the shear band reinforcement in place.

[0074] Thus, particular embodiments of the rubber composition may include between 20 and 50 phr or between 20 and 40 phr of reinforcing filler, but are limited to containing no more than 35 phr of total carbon black, or alternatively less than 30 phr, no more than 27 phr, no more than 20 phr, no more than 10 phr, or no more than 5 phr of carbon black. The total amount of carbon black included within the target surface area (at 15 m2 / g and 45m 2 / g or alternatively between 32m 2 / g and 39m 2 The target surface area is preferably an amount between 0 phr and 5 phr, or alternatively between 0 phr and 3 phr. Specifically, for suitable carbon blacks, 0 phr of the carbon black exceeds the target surface area.

[0075] The reinforcing filler may be carbon black or a combination of carbon black and silica.

[0076] In those embodiments comprising a combination of silica and carbon black, the total amount of filler does not exceed 50 phr and the amount of carbon black is at least 5 phr, with the remainder being silica. The weight ratio of carbon black to silica is not particularly limited, but may be, for example, between 1:7 and 7:1 or alternatively between 1:5 and 5:1, between 1:3 and 3:1, or between 1:2 and 2:1. That is, the amount of carbon black may be between approximately 12% and 88% by weight of the total amount of reinforcing filler, or alternatively between 17% and 83% by weight, between 25% and 75% by weight, or between 33% and 66% by weight of carbon black of the total amount of reinforcing filler.

[0077] In the first part, silica is targeted at a surface area of ​​40m 2 / g and 55m 2 / g or alternatively between 40m 2 / g and 47m 2 / g or between 41m 2 / g and 45m 2 / g of low surface area silica, examples of which have been provided above. In the second part, the filler is a target surface area of ​​15m 2 / g and 32m 2 / g or alternatively between 32m 2 / g and 39m 2 / g of carbon black. As mentioned above, the surface area is measured according to ASTM D1993. Of course, the first part can include one or more suitable silica products, and the second part can include one or more suitable products, as long as they each have the surface area required for their part.

[0078] The use of two different types of fillers provides the rubber composition with the desired low hysteresis properties within the desired stiffness range. Carbon black provides the desired stiffness to the rubber composition, but if too much is used, the desired hysteresis level cannot be achieved. Similarly, low-surface-area silica provides the desired hysteresis but not the desired stiffness. Thus, in combination, silica and carbon black provide a rubber composition with the desired low hysteresis properties at the desired stiffness level.

[0079] The combination of fillers of the rubber compositions disclosed herein may include between 25 phr and 60 phr of total reinforcing fillers, or alternatively between 40 phr and 55 phr or between 45 phr and 55 phr. In such rubber compositions having a total amount of reinforcing fillers, the low surface area silica may account for between 35 wt % and 70 wt %, or alternatively between 40 wt % and 68 wt %, between 45 wt % and 65 wt %, or between 48 wt % and 65 wt % of the total weight of the reinforcing fillers in the rubber composition. The remainder of the total amount of reinforcing fillers will be a second portion as carbon black.

[0080] For those embodiments that include silica as a reinforcing filler, a silica coupling agent may be included. Such coupling agents are well known and are at least bifunctional to provide sufficient chemical and / or physical bonding between the inorganic reinforcing filler and the diene elastomer. Examples of such coupling agents include bifunctional organosilanes or polyorganosiloxanes. Specific well-known examples of coupling agents include 3,3'-bis(triethoxysilylpropyl) disulfide (TESPD) and 3,3'-bis(triethoxysilylpropyl) tetrasulfide (TESPT).

[0081] In order to obtain optimal rolling resistance for a tire having a shear band disclosed herein, the shear layer is made of the rubber composition described above to provide ultra-low hysteresis and sufficient stiffness and rubber cohesion to hold the shear band reinforcement in place. Thus, particular embodiments of the rubber composition have the following set of physical properties: ultra-low hysteresis as measured by tan delta ("tan δ") measured at 23°C and 50% strain of between 0.013 and 0.025 or alternatively between 0.013 and 0.022; a shear modulus G* measured at 23°C and 50% strain of at least 1.30 MPa or alternatively between 1.30 MPa and 1.80 MPa; and a strain at break of greater than 80% or alternatively between 80% and 350%, between 80% and 200%, between 100% and 350%, or between 100% and 200%.

[0082] In addition to the above-mentioned rubber component and reinforcing filler, the rubber composition disclosed herein may further include a curing system. Specific embodiments cure with a sulfur curing system that includes free sulfur and may further include, for example, one or more accelerators, stearic acid, and zinc oxide. Suitable free sulfur may include, for example, crushed sulfur, rubber manufacturer's sulfur, commercial sulfur, and insoluble sulfur. The amount of free sulfur included in the rubber composition is unrestricted, and the range may be, for example, between 0.5phr and 10phr, or alternatively between 0.5phr and 5phr or between 0.5phr and 3phr. Specific embodiments may exclude the free sulfur added in the curing system and may instead include a sulfur donor. Specific embodiments particularly exclude peroxide curing systems, so that the curing system does not include peroxides.

[0083] Accelerator is used to control the time and / or temperature required for vulcanization and to improve the property of the rubber composition of solidification.Specific embodiments of the present invention include one or more accelerators.An example of the main accelerator that can be used for being applicable to the present invention is sulfenamide.The example of the sulfenamide accelerator that is applicable to includes n-cyclohexyl-2-benzothiazole sulfenamide (CBS), N-tert-butyl-2-benzothiazole sulfenamide (TBBS), N-oxydiethyl-2-benzothiazole sulfenamide (MBS) and N'-dicyclohexyl-2-benzothiazole sulfenamide (DCBS).The combination of accelerator is often used for improving the property of vulcanized rubber composition, and specific embodiments includes adding secondary accelerator.

[0084] As is known in the art, other additives may be added to the rubber composition disclosed herein. Such additives may include, for example, some or all of the following: antidegradants, antioxidants, fatty acids, waxes, stearic acid, and zinc oxide. Examples of antidegradants and antioxidants include 6PPD, 77PD, IPPD, and TMQ, and may be added to the rubber composition in amounts of, for example, 0.5 phr and 5 phr. Zinc oxide may be added in amounts of, for example, between 1 phr and 6 phr, or alternatively, between 1.5 phr and 4 phr. Wax may be added in amounts of, for example, between 1 phr and 5 phr.

[0085] It should be noted that due to the relatively low stiffness and cohesion of the rubber compositions disclosed herein, certain embodiments of the rubber compositions do not include plasticizers, which include oils and / or resins.

[0086] The rubber composition as an embodiment of the present invention can be produced in a suitable mixer in a manner known to those skilled in the art, generally using two consecutive preparation stages, a first stage of thermomechanical work at an elevated temperature followed by a second stage of mechanical work at a lower temperature.

[0087] The first stage of thermomechanical work (sometimes called the "non-productive" stage) is aimed at thoroughly mixing the various ingredients of the composition, with the exception of the vulcanizing system, by kneading. It is carried out in suitable kneading equipment, such as internal mixers or extruders, until a maximum temperature of generally between 120° C. and 190° C., more strictly between 130° C. and 170° C., is reached under the action of mechanical work and high shear forces exerted on the mixture.

[0088] After the mixture has cooled, a second stage of mechanical work is carried out at a lower temperature. Sometimes called the "production" stage, this finishing stage consists of incorporating the vulcanization (or crosslinking) system (sulfur or other vulcanizing agent and one or more accelerators) by mixing in suitable equipment (e.g., an open mill). It is carried out within an appropriate time (usually between 1 and 30 minutes, for example, between 2 and 10 minutes) and at a sufficiently low temperature below the vulcanization temperature of the mixture in order to prevent premature vulcanization.

[0089] It should be noted that the foregoing includes detailed references to specific embodiments of the present invention, which are provided by way of explanation of the present invention. For example, features shown or described as part of one embodiment can be used with another embodiment to yield a third embodiment. The present invention is further illustrated by the following examples, which are to be considered merely illustrative and not limiting of the present invention in any way. The properties of the compositions disclosed in the examples were evaluated as described below, and these methods are applicable to measuring the properties required by the present invention.

[0090] The modulus of elongation (MPa) is measured based on ASTM standard D412 at 10% (MA10), 100% (MA100) at a temperature of 23° C. on dumbbell test pieces. The measurement is made in the second elongation; that is, after the acclimation cycle. These measurements are the secant modulus in MPa based on the initial cross section of the test piece.

[0091] Elongation properties are measured as elongation at break (%) and the corresponding elongation stress (Mpa), which are measured on ASTM C test pieces at 23°C according to ASTM standard D412.

[0092] The dynamic properties of the rubber composition were measured according to ASTM D5992-96 on a Metravib VA400 viscoelastic analyzer test system at 23°C. The reaction of the sample (double shear geometry, wherein each of two 10mm diameter cylindrical samples is 2mm thick) of the vulcanized material was recorded as being subjected to alternating single sinusoidal shear stresses at a frequency of 10Hz at a controlled temperature of 23°C. Scanned with a deformation amplitude of 0.05% to 90% (outward circulation) and then 90% to 0.05% (return circulation). The loss tangent tan δ was measured at its maximum value, 50% strain during the outward circulation. Complex shear modulus G* was measured at 50% strain during the outward circulation.

[0093] Example 1

[0094] Rubber compositions were prepared using the components shown in Table 1. The amount of each component making up the rubber composition is given in parts per hundred parts by weight of rubber (phr).

[0095] The anti-reversion chemical used was hexamethylene 1,6-bis(thiosulfate) disodium salt dihydrate, also known as "HTSNA" (CAS No. 5719-73-3), available from Eastman / Flexis under the trade name "Duralink HTS".

[0096] Carbon black has a surface area of ​​35m 2 / g of N650. The silica was Evonik Exp 7031-1, which has a surface area of ​​41m 2 / g of powder. CTP is N-(cyclohexylthio)phthalimide, a retarder for sulfur-curing elastomers.

[0097] The cure package contains sulfur, accelerators, stearic acid and zinc oxide.

[0098] Table 1 - Example 1 Rubber Formulation

[0099] preparation W1 F1 F2 F3 F4 F5 NR 70 70 70 70 70 70 BR 30 30 30 30 30 30 N650 17.5 17.5 17.5 17.5 17.5 17.5 EXP7031-1 22 22 22 22 22 22 SI69 0.4 0.4 0.4 0.4 0.4 0.4 DPG 0.05 0.05 0.05 0.05 0.05 0.05 stearic acid 1 1 1 1 1 1 zinc oxide 5 5 5 5 5 5 6PPD 1.3 1.3 1.3 1.3 1.3 1.3 Aflux 1.75 1.75 1.75 1.75 1.75 1.75 Escorez 1102 0.5 0.5 0.5 0.5 0.5 0.5 HTSNA 0.5 1 1.5 2 2.5 sulfur 6.94 6.9 6.9 6.9 6.9 6.9 CBS 2.2 2.2 2.2 2.2 2.2 2.2 CTP 0.4 0.4 0.4 0.4 0.4 0.4

[0100] The rubber formulation was prepared by mixing the components listed in Table 1, except for the accelerator and sulfur, in a Banbury mixer until a temperature between 110° C. and 170° C. was reached. The accelerator and sulfur were added in a second stage on the mill. Vulcanization was carried out at 150° C. for 15 minutes. The formulation was then tested to measure its properties, the results of which are shown in Table 2.

[0101] Table 2 - Rubber properties of Example 1

[0102]

[0103]

[0104] It can be noted that tan delta at 50% strain is lower in all formulations compared to the reference, and modulus also shows an increase of 4% to 12% in all formulations. Such improvements are surprising considering that anti-reversion chemicals do not typically cause such improved material properties in rubber formulations.

[0105] F2 and F3 showed particularly surprising improvements, with tan delta at 50% strain showing a 27% and 23% decrease, respectively, compared to the reference formulation, while modulus at 50% strain showed a 12% and 9% increase, respectively, compared to the reference formulation.

[0106] Example 2

[0107] The components shown in Table 2A were used to prepare rubber compositions having silica and carbon black as reinforcing fillers. The amounts of each component making up the rubber composition were provided in parts per hundred parts by weight of rubber (phr). Many of the materials were the same as those disclosed in Example 1.

[0108] Table 3 - Example 2 Rubber Formulation

[0109] preparation W1 F1 F2 F3 F4 F5 NR 70 70 70 70 70 70 BR 30 30 30 30 30 30 N650 17.5 17.5 17.5 17.5 17.5 17.5 EXP7031-1 22 22 22 22 22 22 SI69 0.4 0.4 0.4 0.4 0.4 0.4 DPG 0.05 0.05 0.05 0.05 0.05 0.05 stearic acid 1 1 1 1 1 1 zinc oxide 5 5 5 5 5 5 6PPD 1.3 1.3 1.3 1.3 1.3 1.3 Aflux 1.75 1.75 1.75 1.75 1.75 1.75 Escorez 1102 0.5 0.5 0.5 0.5 0.5 0.5 D900 0.46 0.91 1.37 1.83 2.28 sulfur 6.94 6.9 6.9 6.9 6.9 6.9 CBS 2.2 2.2 2.2 2.2 2.2 2.2 CTP 0.4 0.4 0.4 0.4 0.4 0.4

[0110] A rubber formulation was prepared in the same manner as in Example 1. Similar to Example 1, the low surface area silica was Evonik Exp7031-1, which has a surface area of ​​41 m 2 / g of powder, and the carbon black is N650.

[0111] The anti-reversion chemical used in Example 2 was 1,3-bis((3-methyl-2,5-dioxopyrrol-1-yl)methyl)benzene, also known as "D900" (CAS No. 119462-56-5), available from Lanxess under the trade name "Perkalink 900".

[0112] Table 4 - Rubber properties of Example 2

[0113] nature W2 F6 F7 F8 F9 F10 Tan δ 50% 0.027 0.020 0.020 0.022 0.024 0.022 Max Tand 0.047 0.064 0.076 0.082 0.100 0.085 G*(50％) 1498.20 1327.30 1320.50 1371.80 1266.00 1264.40 Tan δ 50% Index -26％ -26％ -19％ -11％ -19％ G*(50%) index -11％ -12％ -8％ -15％ -16％

[0114] It can be noted that tan δ at 50% strain is lower in all formulations compared to the reference, and modulus also shows a decrease of 8% to 16% in all formulations. Such an improvement in tan δ at 50% shows a decrease in hysteresis and is surprising considering that anti-reversion chemicals do not typically cause such improved material properties in rubber formulations.

[0115] As used in the claims and description herein, the terms "comprising," "including," and "having" should be considered to indicate an open group that may include unspecified other elements. As used in the claims and description herein, the term "consisting essentially of..." should be considered to indicate a partial open group that may include unspecified other elements, as long as those other elements do not substantially change the basic and novel characteristics of the claimed invention. The terms "one," "an," and words in the singular should be understood to include the same words in the plural form, so that the term means providing one or more of something. The terms "at least one" and "one or more" are used interchangeably. The terms "one" or "single" will be used to indicate that one and only one of something is intended to be used. Similarly, when a specific number of things is expected, other specific integer values, such as "two," are used. The terms "preferably," "preferred," "preferably," "optionally," "possibly," and similar terms are used to indicate that the mentioned clauses, conditions, or steps are optional (non-essential) features of the present invention. A range described as "between a and b" includes the values ​​of "a" and "b."

Claims

1. An annular shear band defining an axial direction, a radial direction, and a circumferential direction, the annular shear band comprising: an annular shear layer, the annular shear layer being composed of a rubber composition; a plurality of discrete annular reinforcing elements positioned throughout the annular shear layer along a plurality of axially-oriented rows, the reinforcing elements being separated from one another by a predetermined distance, each reinforcing element having a center point, wherein the reinforcing elements are staggered along the axial direction or the radial direction of the shear band such that the center points of the reinforcing elements of adjacent axially-oriented rows are arranged to form a rhombus having non-orthogonal angles between sides, wherein the rubber composition is based on a crosslinkable rubber composition comprising, in parts by weight per 100 parts by weight of rubber (phr): between 50 and 100 phr of natural rubber; between 0 and 50 phr of a second rubber component selected from the group consisting of polybutadiene rubber, copolymers of polybutadiene and styrene, and combinations thereof, wherein the copolymers have no more than 5 mole percent styrene; Between 25 phr and 60 phr of reinforcing filler, the reinforcing filler being limited to a first portion and a second portion, the first portion being between 35 wt% and 70 wt% of the total reinforcing filler silica and having a ratio of 40 m 2 / g and 55m 2 / g, the second part is between 30% and 65% by weight of the total amount of the reinforcing filler and has a surface area of ​​15m 2 / g and 45m 2 Target surface area between / g; Between 0.5 and 2.5 phr of the anti-reversion chemical hexamethylene 1,6-bis(thiosulfate) disodium salt dihydrate; and Sulfur curing system.

2. The endless shear band of claim 1, wherein the anti-reversion chemical is between 1 and 2 phr.

3. The annular shear zone of claim 1 , wherein the target surface area of ​​the first portion of the silica is within 40 m 2 / g and 45m 2 / g.

4. The endless shear band of claim 3, wherein the target surface area of ​​the second portion of the carbon black is between 32 m 2 / g and 39m 2 / g.

5. The endless shear band according to claim 4, wherein the rubber composition comprises 100 phr of natural rubber.

6. The endless shear band of claim 4 , wherein the crosslinkable rubber composition further comprises between 0 and 20 phr of a third rubber component, the third rubber component being a functionalized styrene-butadiene copolymer having between 1 and 35 mol % styrene, wherein the styrene-butadiene copolymer is functionalized with a moiety capable of combining with a silica reinforcing filler.

7. The endless shear band of claim 6, wherein the rubber composition has a tan δ measured at 23°C and 80% strain of between 0.015 and 0.025, a shear modulus G* measured at 23°C and 80% strain of at least 1.30 MPa, and a strain at break greater than 80%.

8. The annular shear band of claim 7, wherein the tan delta is between 0.015 and 0.

022.

9. The annular shear band of claim 8, wherein the shear modulus G* is between 1.30 MPa and 2.0 MPa.

10. An annular shear band according to any one of the preceding claims, wherein the reinforcing elements each have a nominal diameter Φ, and wherein adjacent axially oriented rows of the reinforcing elements are separated from each other by a predetermined distance w s , the predetermined distance is in the range between Φ / 2 and Φ / 10, or is Φ / 4.

11. An annular shear band according to any one of claims 1 to 9, wherein the reinforcing elements each have a nominal diameter Φ, wherein non-adjacent axially oriented rows of the reinforcing elements are separated from each other by a predetermined distance w of about Φ / 4 s , and wherein adjacent axially oriented rows of said reinforcing elements are separated from each other by said predetermined distance w of about Φ / 4. s .

12. An annular shear band according to any one of claims 1 to 9, wherein the reinforcing elements each have a nominal diameter Φ, wherein adjacent axially oriented rows of the reinforcing elements are separated from each other by a predetermined distance w of about Φ / 4 s , and wherein adjacent reinforcing elements along an axially oriented row of said reinforcing elements are separated from each other by said predetermined distance w of about Φ / 4 s .

13. The annular shear band according to any one of claims 1 to 9, the shear band having a nominal diameter ND, and wherein the reinforcing elements each have a nominal diameter Φ in the range of about ND / 200 to about ND / 1000.

14. The endless shear band according to any one of claims 1 to 9, wherein the reinforcing element comprises metal, nylon, PET or glass fiber impregnated in a thermosetting resin.

15. A non-pneumatic wheel comprising an annular shear band according to any one of the preceding claims.

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