BICYCLE BANDAGE

Abstract

The invention relates to a bicycle tire comprising a tread having improved wet grip, the tread comprising a rubber composition based on at least one elastomer matrix comprising at least one butadiene-styrene copolymer, 10 to 60 parts per annum of a reinforcing filler comprising silica, and a crosslinking system, the rubber composition of the tread having a glass transition temperature in the range of -30.0°C to -10.0°C.

Description

Title of the invention: BICYCLE BANDAGE

[0001] The present invention relates to bicycle tires, in particular to the rubber composition of their tread which is intended to come into contact with the ground when riding.

[0002] Bicycle tire treads must meet a large number of technical requirements, often conflicting, including rolling resistance, grip on both dry and wet surfaces, wear resistance, rigidity of the cured compositions, while taking into account the curing properties and viscosity of their composition in the raw state (associated with the ease of industrial implementation of the compositions, or processability).

[0003] Given the environmental challenges associated with transportation, bicycles are increasingly used for both commuting and leisure. This increased use results from a rise in the number of users, as well as an increase in the frequency with which these users cycle. In particular, weather conditions are becoming less and less of a deterrent to cycling. In this context, one of the main challenges for bicycle tires is to provide good grip on wet surfaces.

[0004] To improve the wet grip of bicycle tires, it is known to increase the tread depth, that is, to increase, within a certain limit, the number of grooves, channels, or sipes in the tread. Thus, the main solutions for improving wet grip lie in modifying the tread pattern or architecture.

[0005] However, it is still advantageous to further improve the wet grip of bicycle tires, preferably without degrading other expected properties, such as rolling resistance, dry grip and wear resistance.

[0006] There is therefore a need for bicycle tires with improved wet grip, without impacting other tire performance, in particular rolling resistance, which reflects the energy supplied by the cyclist or by the battery when the bicycle is electrically assisted, the rigidity of the baked compositions, which reflects the ability to keep the handlebars straight after contact with a branch or stone or contact with the ground after a jump, dry grip and wear resistance.

[0007] Bicycle tires, due to the nature of these vehicles (weight, wheel size, tire architecture and geometry, conditions of use, etc.), are subject to very specific constraints. The simple transposition of existing solutions from other fields, for example that of motorcycle tires, to the field of bicycle tires is therefore not considered by a person skilled in the art of bicycle tires.

[0008] Continuing its research, the Applicant unexpectedly discovered that it was possible to improve the wet grip of bicycle tires by using a specific rubber composition in the tread of the tire.

[0009] Thus, the invention relates to a bicycle tire comprising a tread, the tread comprising a rubber composition based on at least: - an elastomeric matrix comprising at least one butadiene-styrene copolymer, - 10 to 60 parts per annum of a reinforcing filler comprising silica, and - a crosslinking system, in which, the rubber composition of the tread has a glass transition temperature in the range of -30.0°C to -10.0°C, preferably from -26.0°C to -15.5°C, preferably from -25.0°C to -16.0°C.

[0010] In this document, unless otherwise indicated, the expressions "rubber composition" or "composition(s) according to the invention" refer to the rubber composition of the tread of the bicycle tire according to the invention. I- DEFINITIONS

[0011] The expression "composition based on" means a composition comprising the mixture and / or the in situ reaction product of the different constituents used, some of these constituents being able to react and / or being intended to react with each other, at least partially, during the different phases of manufacturing the composition; the composition can thus be in a totally or partially crosslinked state or in a non-crosslinked state.

[0012] By "elastomeric matrix" is meant all the elastomers in the composition, including any ethylene-propylene-diene (EPDM) copolymers that may be present.

[0013] Unless otherwise indicated, the rates of units resulting from the insertion of a monomer into a copolymer are expressed as a molar percentage relative to the total monomer units of the copolymer.

[0014] The expression "part by weight per hundred parts by weight of elastomer" (or pce) is to be understood in the context of the present invention as the part, by mass per hundred parts of elastomer present in the rubber composition considered, including any EPDM.

[0015] In the present, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by mass.

[0016] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​from greater than a to less than b (i.e., excluding the bounds a and b), while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​from a to b (i.e., including the strict bounds a and b). In the present case, when an interval of values ​​is designated by the expression "from a to b", the interval represented by the expression "between a and b" is also and preferably designated.

[0017] The compounds mentioned in the description may be of fossil origin or bio-based. In the latter case, they may be partially or totally derived from biomass or obtained from renewable raw materials derived from biomass. Similarly, the compounds mentioned may also come from the recycling of materials already in use, that is to say, they may be partially or totally derived from a recycling process, or obtained from raw materials themselves derived from a recycling process. This includes, in particular, polymers, plasticizers, fillers, etc.

[0018] Unless otherwise indicated, the glass transition temperature “Tg” of the ingredients present in a composition is measured in a known manner by DSC (Differential Scanning Calorimetry) according to ASTM D3418 (1999).

[0019] The Tg of the rubber compositions is measured using a VA400 viscoanalyzer marketed by Metravib, in accordance with ASTM D5992-96. The response of a crosslinked material sample (double shear geometry, each of the two cylindrical samples 10 mm in diameter and 2 mm thick) was recorded while subjected to a single alternating sinusoidal shear stress of constant value 0.34 MPa at a frequency of 10 Hz over a temperature sweep from -60°C to 100°C, with the temperature increasing at a rate of 1.5°C / min. The temperature at which the maximum tan(φ) occurred was recorded as the Tg of the composition. II- DESCRIPTION OF THE INVENTION II-1 Rubber Composition

[0020] The rubber composition of the tread of the tire according to the invention has the essential characteristic of exhibiting a Tg within a range from -30.0°C to -10.0°C. The Tg of the rubber composition is, as is well known to those skilled in the art, measured on the composition in the crosslinked state, that is to say after crosslinking of said composition.

[0021] This specific Tg range, combined with a specific rate of reinforcing filler including silica, makes it possible to obtain, unexpectedly, an improvement in the wet grip of bicycle tire tread compositions.

[0022] A person skilled in the art knows how to obtain a rubber composition having a determined Tg thanks to the nature and levels of the ingredients which he uses in the rubber composition, in particular thanks to the Tgs and levels of the elastomers, and to the Tgs and levels of the plasticizers (plasticizing resins and / or liquid plasticizer at 23°C) possibly present in the composition.

[0023] In a particularly advantageous manner, especially for grip on wet ground, the rubber composition of the tread of the tire according to the invention has a Tg within a range of -26.0°C to -15.5°C, preferably from -25.0°C to -16.0°C.

[0024] The elastomeric matrix of the rubber composition of the tread of the tire according to the invention comprises at least one styrene-butadiene rubber compound (SBR). Indeed, SBRs have the advantage of exhibiting very wide temperature ranges, from -90°C to 0°C, which is useful for those skilled in the art who wish to obtain a rubber composition with a specific temperature range. The elastomeric matrix of the rubber composition of the tread of the tire according to the invention may also comprise one or more other diene elastomers, in particular one or more essentially unsaturated diene elastomers.

[0025] By "diene" elastomer (or indistinctly rubber), whether natural or synthetic, is to be understood in a known way as an elastomer consisting at least in part (i.e., a homopolymer or a copolymer) of diene monomer units (monomers bearing two carbon-carbon double bonds, conjugated or not).

[0026] These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". Generally, "essentially unsaturated" means a diene elastomer derived at least in part from conjugated diene monomers, having a proportion of diene motifs or units (conjugated dienes) greater than 15% (mole percent); thus, diene elastomers such as butyl rubbers or EPDM-type diene-alpha-olefin copolymers do not fall under the preceding definition and can be described in particular as "essentially saturated" diene elastomers (low or very low proportion of diene motifs, always less than 15%).

[0027] Suitable conjugated dienes are conjugated dienes having 4 to 12 carbon atoms, in particular 1,3-dienes, such as 1,3-butadiene and isoprene.

[0028] Advantageously, the essentially unsaturated elastomer(s) are one or more diene elastomers derived at least in part from conjugated diene monomers, having a diene motif or unit content greater than 30% by mole, preferably greater than 50% by mole. These are preferably essentially unsaturated elastomers selected from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene copolymers, isoprene copolymers, and mixtures of these elastomers, preferably from polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene-styrene copolymers (SBR), and mixtures of these elastomers.

[0029] Those with a -1,2 unit content (molar %) of between 4% and 80% or those with a cis-1,4 unit content (molar %) greater than 80% are particularly suitable as polybutadiene. Those with a Tg (temperature difference) between 0°C and -90°C, a styrene content between 1% and 60% by weight, and more particularly between 10% and 50%, a -1,2 unit content (molar %) of the butadiene portion between 4% and 75%, and a trans-1,4 unit content (molar %) between 10% and 80% are particularly suitable as butadiene-styrene copolymers. It should be noted that SBR can be prepared as an emulsion (ESBR) or as a solution (SSBR).

[0030] The essentially unsaturated diene elastomer, in particular SBR, can be modified, i.e., either coupled and / or star-shaped, or functionalized, or coupled and / or star-shaped and simultaneously functionalized. Preferably, the SBR in the rubber composition is functionalized with at least one functional group as defined below.

[0031] Thus, the essentially unsaturated diene elastomer can be coupled and / or star-linked, for example by means of a silicon or tin atom that links the elastomer chains together. The essentially unsaturated diene elastomer can simultaneously or alternatively comprise at least one functional group. By functional group is meant a group comprising at least one heteroatom selected from Si, N, S, O, P. Particularly suitable as functional groups are those comprising at least one function such as: a silanol function, an alkoxysilane function, a primary, secondary or tertiary amine function, cyclic or non-cyclic, a thiol function, or an epoxide function.

[0032] Advantageously, the elastomeric matrix comprises a mixture of essentially unsaturated diene elastomers. In particular, it may comprise several butadiene-styrene copolymers that may differ in their Tg.

[0033] In particular, the at least one essentially unsaturated diene elastomer may comprise natural rubber and one or more butadiene-styrene copolymers. In this case, the essentially unsaturated diene elastomer of the elastomer matrix advantageously comprises from 50% to 95% by weight, preferably 70% 90% by weight, of butadiene-styrene copolymer, and 5% to 50% by weight, preferably 10% to 30% by weight, of natural rubber.

[0034] The at least one essentially unsaturated diene elastomer may also further comprise polybutadiene. In this case, the essentially unsaturated diene elastomer of the elastomer matrix may comprise from 5% to 40% by weight, preferably from 10% to 30% by weight, of natural rubber, from 20% to 90% by weight, preferably from 40% to 80% by weight, of butadiene-styrene copolymer, and from 5% to 40% by weight, preferably from 10% to 30% by weight, of polybutadiene. Advantageously, the elastomer matrix does not comprise butadiene or comprises less than 10% by weight, preferably less than 5% by weight, relative to the total weight of the elastomer matrix. Even more preferably, the elastomer matrix does not comprise butadiene.

[0035] The elastomeric matrix may further comprise one or more ethylene-propylene-diene (EPDM) copolymers.

[0036] Any EPDM can be used in the context of the present invention. However, the use of a specific EPDM may be advantageous in the context of the present invention. The EPDM may be a single EPDM or a mixture of several EPDMs.

[0037] In particular, preferably, the EPDM has an ethylene content ranging from 41% to 75% by weight, preferably from 50% to 71.5% by weight, relative to the weight of the EPDM.

[0038] EPDM also advantageously has a propylene content ranging from 13% to 58% by weight, preferably from 17% to 42% by weight, relative to the weight of EPDM.

[0039] EPDM also advantageously has a diene content ranging from 1% to 12% by weight, preferably from 8% to 11.5% by weight, relative to the weight of EPDM.

[0040] The diene of the EPDM can be chosen from the group consisting of ethylidene norbornene, dicyclopentadiene and mixtures thereof. Preferably, the diene of the EPDM is ethylidene norbornene, in particular 5-ethylidene-2-norbomene (ENB).

[0041] The ethylene, propylene and diene levels of EPDM can be determined by infrared according to ASTM D3900 for the ethylene and propylene levels and ASTM D6047 for the diene level.

[0042] The EPDM content in the elastomer matrix of the composition according to the invention is preferably in the range of 5% to 50% by weight, for example 10% to 45% by weight, for example 15% to 40% by weight.

[0043] However, for the purposes of the invention, it may be advantageous for the elastomeric matrix to contain little or no EPDM. Thus, the rubber composition of the tread of the bicycle tire according to the invention advantageously contains no EPDM or less than 4.9% by weight, preferably less than 4% by weight, preferably less than 2% by weight, preferably less than 1% by weight. Preferably, the elastomeric matrix does not contain EPDM.

[0044] Thus, the elastomeric matrix of the rubber composition of the bicycle tire tread advantageously comprises 50% to 100%, preferably 80% to 100%, preferably 95.1% to 100%, preferably 96% to 100%, preferably 98% to 100%, preferably 99% to 100%, by weight, of essentially unsaturated diene elastomer, including at least one butadiene-styrene copolymer. Preferably, it comprises 100% by weight of essentially unsaturated diene elastomer, including at least one butadiene-styrene copolymer.

[0045] The rubber composition of the tread of the bicycle tire according to the invention comprises 10 to 60 parts per annum of a reinforcing filler, known for its ability to strengthen a rubber composition usable for the manufacture of tires. Such a reinforcing filler typically consists of particles whose average size (by mass) is less than one micrometer, generally less than 500 nm, most often between 20 and 200 nm, and in particular and more preferably between 20 and 150 nm.

[0046] According to the invention, the reinforcing filler comprises silica. It may further comprise another reinforcing filler, in particular carbon black.

[0047] Any type of precipitated silica may be suitable, in particular highly dispersible precipitated silicas (known as "HDS" for "highly dispersible" or "highly dispersible silica"). These precipitated silicas, whether highly dispersible or not, are well known to those skilled in the art. Examples include the silicas described in applications WO03 / 016215-A1 and WO03 / 016387-A1. Among the commercial HDS silicas, one can notably use the “Ulsil ® 5000GR”, “Ulsil ® 7000GR” silicas from the company Evonik, the “Zeosil ® 1085GR”, “Zeosil® 1115 MP”, “Zeosil® 1165MP”, “Zeosil® Premium 200MP”, “Zeosil® HRS 1200 MP” silicas from the Solvay Company.As non-HDS silica, the following commercial silicas may be used: “Ultrasil® VN2GR”, “Ultrasil® VN3GR” from Evonik, “Zeosil® 175GR” from Solvay, “Hi-Sil EZ120G(-D)”, “Hi-Sil EZ160G(-D)”, “Hi-Sil EZ200G(-D)”, “Hi-Sil 243LD”, “Hi-Sil 210”, “Hi-Sil HDP 320G” from PPG.

[0048] To couple the silica to the diene elastomer, a coupling agent (or bonding agent) that is at least bifunctional is used in a well-known manner to ensure sufficient chemical and / or physical connection between the inorganic filler (surface of its particles) and the diene elastomer. Organosilanes or polyorganosiloxanes that are at least bifunctional are used in particular. By "bifunctional," we mean a compound having a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the diene elastomer. For example, such a bifunctional compound may comprise a first functional group comprising a silicon atom, said first functional group being able to interact with the hydroxyl groups of an inorganic charge and a second functional group comprising a sulfur atom, said second functional group being able to interact with the diene elastomer.

[0049] Preferably, the organosilanes are chosen from the group consisting of polysulfide organosilanes (symmetric or asymmetric) such as bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated TESPT and marketed under the name "Si69" by Evonik, or bis-(triethoxysilylpropyl) disulfide, abbreviated TESPD and marketed under the name "Si75" by Evonik, polyorganosiloxanes, mercaptosilanes, and blocked mercaptosilanes, such as S-(3-(triethoxysilyl)propyl octanethioate) marketed by Momentive under the name "NXT Silane". More preferably, the organosilane is a polysulfide organosilane.

[0050] The coupling agent content can easily be adjusted by a person skilled in the art. Typically and preferably, the coupling agent content represents 0.5% to 15% by weight relative to the amount of silica.

[0051] Silica advantageously has a specific surface area BET in the range of 140 to 200 m2 / g, preferably 150 to 170 m2 / g, preferably 155 to 168 m2 / g.

[0052] Its specific surface area BET of silica is determined by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" (Vol. 60, page 309, February 1938), and more specifically according to a method adapted from standard NF ISO 5794-1, Annex E of June 2010 [multipoint volumetric method (5 points) - gas: nitrogen - degassing under vacuum: one hour at 160°C - relative pressure range w / in: 0.05 to 0.17].

[0053] Advantageously, the rate of reinforcing charge, in the composition, is within a range of 25 to less than 55 pc, preferably from 30 to 50 pc, preferably from 35 to less than 50 pc.

[0054] The reinforcing filler may comprise carbon black at a rate of less than 10 parts per annum, preferably less than 5 parts per annum. Advantageously, the composition does not comprise carbon black or comprises less than 1 part per annum.

[0055] The reinforcing filler may comprise more than 50% to 100% by weight, preferably 80% to 100% by weight, preferably 95% to 100% by weight, of silica relative to the total weight of the reinforcing filler. In particular, the reinforcing filler may comprise 100% by weight of silica. This is particularly advantageous when coloring the tread of the bicycle tire using pigments.

[0056] The plasticizing system of the rubber composition of the tread of the bicycle tire according to the invention may comprise at least one plasticizing resin having a glass transition temperature above 20°C, referred to as a "high Tg" (also referred to herein as a "plasticizing resin" for the sake of simplicity). As indicated above, plasticizing resins are useful compounds for adjusting the Tg of the rubber composition.

[0057] The term "resin" is reserved in this application, by definition known to those skilled in the art, for a compound which is solid at room temperature (23°C), as opposed to a liquid plasticizing compound such as an oil.

[0058] Plasticizing resins are polymers well known to those skilled in the art, essentially carbon- and hydrogen-based but potentially containing other types of atoms, and are particularly useful as plasticizing or tackifying agents in polymer matrices. They are generally miscible (i.e., compatible) at the ratios used with the polymer compositions for which they are intended, so as to act as true diluents. They have been described, for example, in the book entitled "Hydrocarbon Resins" by R. Mildenberg, M. Zander, and G. Collin (New York, VCH, 1997, ISBN 3-527-28617-9), Chapter 5 of which is devoted to their applications, particularly in pneumatic rubber (5.5. "Rubber Tires and Mechanical Goods"). They can be aliphatic, cycloaliphatic, aromatic, hydrogenated aromatic, of the aliphatic / aromatic type, i.e. based on aliphatic and / or aromatic monomers.They can be natural or synthetic, petroleum-based or not (if so, also known as petroleum resins). Their Tg is preferably above 20°C (most often between 30°C and 95°C).

[0059] As is known, these plasticizing resins can also be described as thermoplastic resins in that they soften upon heating and can thus be molded. They can also be defined by a softening point or temperature. The softening temperature of a plasticizing resin is generally about 50 to 60°C higher than its Tg value. The softening point is measured according to ISO 4625 (Ring and Bail method). The macrostructure (Mw, Mn, and Ip) is determined by size exclusion chromatography (SEC) as described below.

[0060] As a reminder, SEC analysis, for example, consists of separating macromolecules in solution according to their size using columns filled with a porous gel; the molecules are separated according to their hydrodynamic volume, with the largest being eluted first. The sample to be analyzed is simply pre-solubilized in a suitable solvent, tetrahydrofuran, at a concentration of 1 g / liter. The solution is then filtered through a 0.45 µm porosity filter before injection into The equipment. The equipment used is, for example, a "Waters Alliance" chromatographic system under the following conditions: - the elution solvent is tetrahydrofuran; - temperature 35°C; - concentration 1 g / litre; - flow rate: 1 ml / min; - injected volume: 100 pl; - Moore calibration with polystyrene standards; - set of 3 "Waters" columns in series ("Styragel HR4E", "Styragel HR1" and "Styragel HR 0.5"); - detection by differential refractometer (for example "WATERS 2410") which can be equipped with operating software (for example "Waters Millennium").

[0061] A Moore calibration is performed with a series of commercial polystyrene standards with a low Ip value (less than 1.2), of known molar masses, covering the range of masses to be analyzed. The mass average molar mass (Mw), the number average molar mass (Mn), and the polymolecularity index (Ip = Mw / Mn) are deduced from the recorded data (mass distribution curve of the molar masses).

[0062] All molar mass values ​​indicated in this application are therefore relative to calibration curves made with polystyrene standards.

[0063] The plasticizing resin may have at least one, preferably two or three, more preferably all of the following characteristics: - a Tg greater than 25°C (in particular between 30°C and 100°C), more preferably greater than 30°C (in particular between 30°C and 95°C); - a softening point above 50°C (in particular between 50°C and 150°C); - an average number molar mass (Mn) between 300 and 2000 g / mol, preferably between 400 and 1500 g / mol; - a polymolecularity index (Ip) less than 3, preferably 2 (reminder: Ip = Mw / Mn with Mw average molar mass by weight).

[0064] The above-mentioned preferred high Tg plasticizing resins are well known to those skilled in the art and are commercially available, for example sold with regard to: - polylimonene resins: by the company DRT under the name "Dercolyte L120" (Mn=625 g / mol; Mw=1010 g / mol; Ip=l.6; Tg=72°C) or by the company ARIZONA under the name "Sylvagum TR7125C" (Mn=630 g / mol; Mw=950 g / mol; Ip=l.5; Tg=70°C); - C5 / vinylaromatic copolymer resins, in particular C5 / styrene or C5 / C9: by Neville Chemical Company under the names "Super Nevtac 78", "Super Nevtac 85" or "Super Nevtac 99", by Goodyear Chemicals under the name "Wingtack Extra", by Kolon under the names "Hikorez T1095" and "Hikorez Tl 100", by Exxon under the names "Escorez 2101" and "Escorez 1273"; - limonene / styrene copolymer resins: by DRT under the name "Dercolyte TS 105" of the DRT company, by ARIZONA Chemical Company under the names "ZT115LT" and "ZT5100".

[0065] The plasticizing resin having a glass transition temperature above 20°C may be selected from the group comprising or consisting of cyclopentadiene homopolymer or copolymer resins (abbreviated CPD), dicyclopentadiene homopolymer or copolymer resins (abbreviated DCPD), terpene homopolymer or copolymer resins, C5-cut homopolymer or copolymer resins, C9-cut homopolymer or copolymer resins, alpha-methyl-styrene homopolymer or copolymer resins and their mixtures. Preferably, the plasticizing resin is chosen from the group consisting of terpene homopolymer or copolymer resins, C5-cut homopolymer or copolymer resins or C9-cut homopolymer or copolymer resins, preferably the plasticizing resin is chosen from the group consisting of terpene homopolymer or copolymer resins.

[0066] The term "terpene" here includes in a known way the alpha-pinene, beta-pinene and limonene monomers; preferably a limonene monomer is used, a compound which is known to exist in the form of three possible isomers: L-limonene (levorotatory enantiomer), D-limonene (dextrorotatory enantiomer), or dipentene, racemic of the dextrorotatory and levorotatory enantiomers. Suitable examples of vinylaromatic monomers include styrene, alpha-methylstyrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, vinyl-toluene, para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, hydroxystyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene, and any vinylaromatic monomer derived from a C9 cut (or more generally from a C8 to C1 cut).

[0067] In particular, we can mention the plasticizing resins chosen from the group consisting of homopolymer (D)CPD resins, (D)CPD / styrene copolymer resins, polylimonene resins, limonene / styrene copolymer resins, limonene / D(CPD) copolymer resins, C5 / styrene copolymer resins, C5 / C9 copolymer resins, and mixtures of these resins.

[0068] Preferably, the plasticizing resin comprises or is one or more terpene resins, preferably it comprises or is one or more polylimonene resins.

[0069] All the above plasticizing resins are well known to those skilled in the art and are commercially available, for example sold by DRT under the name "Dercolyte" for polylimonene resins, by Neville Chemical Company under the name "Super Nevtac", by Kolon under the name "Hikorez" or by Exxon Mobil under the name "Escorez" for C5 / styrene cut resins or C5 / C9 cut resins, or by Struktol under the name "40 MS" or "40 NS" (mixtures of aromatic and / or aliphatic resins).

[0070] The proportion of the plasticizing resin having a glass transition temperature above 20°C in the rubber composition can be in the range of 5.0% to 20.0% by weight relative to the weight of the rubber composition of the tread of the bicycle tire according to the invention. Preferably, this proportion is in the range of 5.1% to 15.0% by weight, and more preferably 5.2% to 14.0% by weight, relative to the total weight of the rubber composition.

[0071] The proportion of the plasticizing resin having a glass transition temperature above 20°C in the composition according to the invention can be in a range of 10 to 40 parts per cent, preferably 11 to 30 parts per cent.

[0072] Although not necessary for the implementation of the present invention, the plasticizing system of the rubber composition according to the invention may comprise a liquid plasticizer at 23°C, referred to as a "low Tg" plasticizer, that is to say, one which by definition has a Tg below -20°C, preferably below -40°C. In particular, the composition according to the invention may optionally comprise from 0 to 30 parts per cent of liquid plasticizer at 23°C.

[0073] When a liquid plasticizer at 23°C is used, its level in the composition according to the invention can be in a range of 5 to 30 parts per cent, preferably 15 to 25 parts per cent.

[0074] Any liquid plasticizer at 23°C (or extending oil), whether aromatic or non-aromatic, known for its plasticizing properties with respect to diene elastomers, is usable. At room temperature (23°C), these plasticizers or oils, with varying degrees of viscosity, are liquids (that is to say, substances that eventually take the shape of their container), unlike plasticizing resins, which are solid at room temperature.

[0075] Liquid plasticizers at 23°C are particularly suitable, selected from the group comprising or consisting of liquid diene polymers, polyolefin oils, naphthenic oils, paraffinic oils, DAE oils, MES (Medium Extracted Solvates) oils, TDAE (Treated Distillate Aromatic Extracts) oils, RAE (Residual Aromatic Extract oils), oils TRAE (Treated Residual Aromatic Extract) and SRAE (Safety Residual Aromatic Extract oils), mineral oils, vegetable oils, ether plasticizers, ester plasticizers, phosphate plasticizers, sulfonate plasticizers and their mixtures C.

[0076] Preferably, the liquid plasticizer at 23 °C is chosen from the group comprising or consisting of TDAE oils, vegetable oils and their mixtures.

[0077] The crosslinking system used in the rubber compound can be any type of system known to those skilled in the art in the field of tire rubber compounds. It may, in particular, be sulfur-based, and / or peroxide-based, and / or bismaleimide-based.

[0078] Preferably, the crosslinking system is sulfur-based; this is then referred to as a vulcanization system. Advantageously, the vulcanization system is based on molecular sulfur and / or at least one sulfur-donating agent. At least one vulcanization accelerator is also preferably present, and, optionally and also preferably, various known vulcanization activators such as zinc oxide, stearic acid, or equivalent compounds such as stearic acid salts and transition metal salts, guanidine derivatives (in particular diphenylguanidine), or even known vulcanization retarders may be used.

[0079] Sulfur is used at a preferential rate of between 0.5 and 12 parts per annum, in particular between 1 and 10 parts per annum. The vulcanization accelerator is used at a preferential rate of between 0.5 and 10 parts per annum, more preferably between 0.5 and 5.0 parts per annum.

[0080] Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur can be used as an accelerator, in particular accelerators of the thiazole type and their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types. Examples of such accelerators include the following compounds: 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-ter-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-ter-butyl-2-benzothiazyl sulfenimide ("TBSI"), tetrabenzylthiuram disulfide ("TBZTD"), zinc dibenzyldithiocarbamate ("ZBEC") and mixtures of these compounds.

[0081] The rubber compositions of the tread of the tire according to the invention may optionally also include all or part of the usual additives commonly used in elastomer compositions for tires, such as pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents, etc. II-2 Preparation of compositions

[0082] Rubber compositions according to the invention can be manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art: - a first thermomechanical working or mixing phase (the so-called "non-productive" phase), which can be carried out in a single thermomechanical step during which all the necessary constituents, including the elastomeric matrix, the reinforcing filler, and any other miscellaneous additives, with the exception of the crosslinking system, are introduced into a suitable mixer such as a standard internal mixer (for example, a "Banbury" type mixer). The incorporation of the filler into the elastomer can be carried out in one or more stages by thermomechanical mixing.In cases where the filler is already incorporated, in whole or in part, into the elastomer in the form of a masterbatch, as described, for example, in applications WO 97 / 36724 or WO 99 / 16600, the masterbatch is directly mixed, and where applicable, other elastomers or fillers present in the composition that are not in masterbatch form, as well as any other miscellaneous additives other than the crosslinking system, are incorporated. The non-productive phase can be carried out at high temperature, up to a maximum temperature between 110°C and 200°C, preferably between 130°C and 185°C, for a duration generally between 2 and 10 minutes. - a second mechanical working phase (the so-called "productive" phase), which can be carried out in an external mixer such as a roller mixer, after cooling the mixture obtained during the first non-productive phase to a lower temperature, typically below 120°C, for example between 40°C and 100°C. The crosslinking system is then incorporated, and the whole is then mixed for a few minutes, for example between 5 and 15 min.

[0083] Such phases have been described for example in applications EP-A-0501227, EP-A-0735088, EP-A-0810258, WO00 / 05300 or WO00 / 05301.

[0084] The final composition thus obtained is then calendered, for example, into a sheet or plate, particularly for laboratory characterization, or extruded (or co-extruded with another rubber composition) into a semi-finished (or profile) rubber product usable, for example, as a bicycle tire tread. These products can then be used for the manufacture of tires, according to techniques known to those skilled in the art.

[0085] The composition can be either in the raw state (before crosslinking or vulcanization), or in the cooked state (after crosslinking or vulcanization), can be a semi-finished product that can be used in a tire.

[0086] The crosslinking of the composition can be carried out in a manner known to those skilled in the art, for example at a temperature between 130°C and 200°C, under pressure. II-3 Bicycle Bandage

[0087] According to the invention, the tire is intended to equip any type of bicycle without particular limitation, whether or not it has an electric assist motor. Advantageously, the bicycle tire is a tire for (preferably) road bikes, mountain bikes, or hybrid bikes. The hybrid bike can be a so-called "Gravel" or "Cyclo-Cross" bike. The mountain bike can be a touring mountain bike, an all-mountain bike, a cross-country (or XC) mountain bike, a down-country (or DC) mountain bike, a trail bike, or a gravity bike.

[0088] The term "tire" refers to a pneumatic or non-pneumatic tire. Pneumatic bicycle tires typically consist of a carcass reinforcement layer anchored in two beads by folding it around two wires. The beads are radially extended by the carcass ply, which is itself extended by the tread. A pneumatic tire is designed, by definition, to contain compressed air when mounted on the bicycle wheel. A non-pneumatic tire, on the other hand, can be of various forms, for example, a solid or non-solid tire. As an example describing a non-pneumatic bicycle tire, FR3042736A1 may be cited. According to the invention, the tire according to the invention is preferably a pneumatic tire.

[0089] The tire according to the invention may be a tubeless tire, that is, mounted directly on a rim without an inner tube, or a tube-type tire requiring an inner tube. The tire according to the invention may also be a non-pneumatic tire, either solid or airless.

[0090] The width (or section) of the bicycle tire according to the invention can be in the range of 20 to 80 mm, preferably from 30 to 75 mm. The width of the tire is measured on the mounted tire and under the pressure recommended by the manufacturer in the case of pneumatic tires according to ETRTO 2024, "Cycle Tyres", Section B.2, section value "(s)". III- EXAMPLES III-1 Measurements and tests used Dynamic properties

[0091] The dynamic properties (Tg and integral of the observed tan(φ) value from -30°C to 0°C (Int. tan(φ) [-30°C ; 0°C])) of the rubber compositions were measured on a VA400 viscoanalyzer marketed by Metravib, in accordance with ASTM D5992-96. The response of a crosslinked material sample (double shear geometry, each of the two cylindrical samples 10 mm in diameter having a thickness of 2 mm) was recorded while it was subjected to a single alternating sinusoidal shear stress of a constant value of 0.34 MPa and at a frequency of 10 Hz over a temperature sweep from -60°C to 100°C, the temperature increasing at a rate of 1.5°C / min. The temperature at which the maximum tan(ô) appeared was recorded as the glass transition temperature, Tg.

[0092] It should be noted that, as is well known to those skilled in the art, the integral of the observed tan(φ) value from -30°C to 0°C is representative of the wet surface adhesion. The performance results Int. tan(φ) [-30°C; 0°C] are expressed as a base of 100, with the value 100 being assigned to the control TL. A result greater than 100 indicates that the composition exhibits better wet surface adhesion. III-2 Preparation of compositions

[0093] In the following examples, the rubbery compositions were produced as described in section II.2 above. In particular, the "non-productive" phase was carried out in a 0.4-liter mixer for 3.5 minutes, at an average paddle speed of 50 revolutions per minute, until a maximum drop temperature of 160°C was reached. The "productive" phase was carried out in a roller tool at 23°C for 5 minutes.

[0094] The crosslinking of the composition was carried out at a temperature between 130°C and 200°C, under pressure. III-3 Tests of Rubber Compositions

[0095] The examples presented below are intended to compare the wet surface adhesion performance of compositions according to the present invention (Cl to C3) with control compositions (Tl to T2).

[0096] Table 1 presents the compositions tested (in parts per annum), as well as the results obtained. In addition to the ingredients presented in Table 1, the tested formulations all contain 1.5 parts per annum of cyclic acetal “Vulkazon AFS / LG” from Lanxess, 2 parts per annum of ozone-blocking wax “VARAZON 4959” from Sasol Wax, 2 parts per annum of black pigment “MICROLEN BK 0062 MCN” from Sun Chemical, 1.5 parts per annum of diphenylguanidine “Perkacit DPG” from Flexsys, 3.5 parts per annum of industrial-grade zinc oxide from Umicore, 2 parts per annum of stearic acid “Pristerene 4931” from Uniqema, 3.5 parts per annum of sulfur, and 2 parts per annum of N-cyclohexyl-2-benzothiazol- sulfenamide “Santocure CBS” from the company Flexsys, as a vulcanization accelerator.

[0097] [Tables 1] Compositions Tl Cl C2 C3 T2 NR(1) 15 15 15 15 - SBR(2) 55 20 20 20 - SBR(3) - - - - 50 SBR(4) - 65 65 35 50 EPDM(5) 30 - - 30 - Plasticizing resin(6) 5 22 11 22 - Mass percentage of (6) 2.7% 72.2% 5.4% 72.2% 0% Liquid plasticizer(7) 10 - - - - Liquid plasticizer(8) - - 22 - 74.75 Silica(9) 45 35 50 35 108 Coupling agent(10) 3.6 2.8 4.0 2.8 8.0 Tg of composition -13.0°C -23.0°C -23.0°C -16.0°C -18.0°C Performance Wet grip 100 148 149 134 103

[0098] (1) Natural rubber (2) SBR “Sprintan® SLR 4602” from the company Resinex (Tg = -25 °C) (3) SBR with 40% styrene motifs and 16% polybutadiene 1,2 motifs in the butadiene part, 14% cis motif in the butadiene part and 70% trans motif in the butadiene part (Tg = -30°C) (4) SBR “Sprintan® SLR 3402” (Tg = -62°C) (5) EPDM “Keltan 3960” from Arlanxeo with 56% ethylene pattern and 11% ENB pattern (6) Polylimonene resin “Dercolyte L120” from the company DRT (Tg = 72°C) (7) Paraffinic oil “Tudalen 1968” from the Klaus Dahleke company (8) TDAE oil “Flexon 630” from the Shell company (9) Silica “Zeosil 1165MP” from the Solvay company (10) Liquid silane triethoxysilylpropyltetrasulfide (TESPT) “Si69” from the Evonik company

[0099] Furthermore, the results presented in Table 1 above show that all compositions according to the invention, exhibiting both a charge level Reinforcing composition including 10 to 60 parts silica and a Tg of -30.0°C to -10.0°C, greatly improves adhesion on wet ground compared to compositions whose Tg is not between -30.0°C and -10.0°C, or compared to a composition not including 10 to 60 parts reinforcing filler including silica.

Claims

Demands

1. Bicycle tire comprising a tread, the tread comprising a rubber composition based on at least: - an elastomeric matrix comprising at least one butadiene-styrene copolymer, - 10 to 60 parts per annum of a reinforcing filler comprising silica, and - a crosslinking system, wherein the rubber composition of the tread has a glass transition temperature in the range of -30.0°C to -10.0°C.

2. Bandage according to claim 1, wherein the glass transition temperature of the rubber composition is in a range from -26.0°C to -15.5°C.

3. Bandage according to claim 1, wherein the glass transition temperature of the rubber composition is in a range from -25.0°C to -16.0°C.

4. Bandage according to any one of the preceding claims, wherein the reinforcing filler comprises more than 50% to 100% by weight, preferably 80% to 100% by weight of silica relative to the total weight of reinforcing filler.

5. Bandage according to any one of the preceding claims, wherein the rate of reinforcing filler in the rubber composition is in the range of 25 to less than 55 pc, preferably 30 to 50 pc, preferably 35 to less than 50 pc.

6. Bandage according to any one of the preceding claims, wherein the silica has a specific surface area BET in the range of 140 to 200 m2 / g, preferably 150 to 170 m2 / g, preferably 155 to 168 m2 / g.

7. Bandage according to any one of the preceding claims, wherein the reinforcing filler comprises carbon black at a rate of less than 10 pc, preferably less than 5 pc.

8. Bandage according to any one of the preceding claims, wherein the rubber composition comprises from 5.0% to 20.0% by weight, preferably from 5.1% to 15.0% by weight, of at least a plasticizing resin exhibiting a Tg greater than 20°C, relative to the weight of the rubber composition.

9. Bandage according to claim 8, wherein the plasticizing resin is selected from the group consisting of cyclopentadiene homopolymer or copolymer resins, dicyclopentadiene homopolymer or copolymer resins, terpene homopolymer or copolymer resins, C5-cut homopolymer or copolymer resins, C9-cut homopolymer or copolymer resins, alpha-methylstyrene homopolymer or copolymer resins and mixtures thereof, preferably the plasticizing resin is selected from the group consisting of terpene homopolymer or copolymer resins, C5-cut homopolymer or copolymer resins or C9-cut homopolymer or copolymer resins.

10. Bandage according to any one of claims 8 to 9, wherein the rate of plasticizing resin in the rubber composition is in the range of 10 to 40 parts per annum, preferably 11 to 30 parts per annum.

11. Bandage according to any one of the preceding claims, wherein the elastomeric matrix of the rubber composition does not comprise ethylene-propylene-diene copolymer or comprises less than 4.9% by weight, preferably less than 4% by weight.

12. Bandage according to any one of claims 1 to 10, wherein the elastomeric matrix of the rubber composition does not comprise ethylene-propylene-diene copolymer.

13. Bandage according to any one of the preceding claims, wherein the crosslinking system of the rubber composition is based on molecular sulfur and / or at least one sulfur-donating agent.

14. Bandage according to any one of the preceding claims, wherein the bicycle bandage is a road bike, mountain bike or all-terrain bike bandage, preferably, the bicycle bandage is an all-terrain bike or all-terrain bike bandage.

15. Bandage according to any one of the preceding claims, wherein the width of the bandage is in a range from 20 to 80 mm, preferably from 30 to 75 mm.