FIELD OF THE INVENTION

The present invention relates to the field of rubber composition. The present invention in particular relates to the NR: PBR blend and NR:SBR:PBR blend-based motorcycle tyre tread base rubber composition using recovered carbon black (rCB) and its method thereof.

BACKGROUND OF THE INVENTION

Carbon black is used as a filler, pigment and/or reinforcing material in polymer composites, for example, in rubbers and in plastic master batches. Manufacturers require consistent quality and consistency in the carbon black. Price is also a major factor when selecting a carbon black. Tire companies and compounders do selection of a carbon black based on its dispersive properties, hardness of the pellet, colloidal properties of the carbon black based on the end-product requirements and its functions. Quality is increasingly being recognized as an aspect of cost savings and thus as a basis for competition.

As the continuing accumulation of scrap tires has become a major global environmental hazard, there has been an increased focus on processes and methods for reclaiming the components of scrap rubber, including tire rubber. One of the materials reclaimed from tyres particularly from end of life tyre tyres through pyrolysis method has been recovered carbon black (rCB).

Reference made to the following patents:

US2015045497 provides a polymer composite comprising at least one polymer and a reclaimed pyro lyzed carbon black (pCB), wherein the pCB comprises less than about 10 pg/g of polycyclic aromatic hydrocarbons (PAH). Also provided are polymer composite and consumer-ready formulations of the low PAH pCB and methods of manufacturing such composites and formulations.

This includes use of pyrolyzed carbon black in SBR:BR (70:30) blend based carbon black filled high traction tyre tread compound and in NR:BR (50:50) blend based tyre sidewall compound whereas the present invention discusses about the use of recovered carbon black (rCB) in NR:SBR:PBR (70:15:15) tri blend and NR:PBR (70:30) di blend based motorcycle tyre tread base composition. Both the rubber compositions are totally different from each other.

IN202017001676/ WO2019028286 talks about crumb rubber obtained from recycled tires subjected to an interlinked substitution process. The process utilizes a reactive component that interferes with sulfur bonds. The resulting treated rubber exhibits properties similar to those of the virgin composite rubber structure prior to being granulated, and is suitable for use in fabricating new tires, engineered rubber articles, and asphalt rubber for use in waterproofing and paving applications.

Use of crumb rubber obtained from recycled tyres is subjected to a process involving phase reticulation induced sulfidic metathesis in NR based tyre base compound whereas the present invention discusses about the use of recovered carbon black (rCB) derived from end -of- life tyres in NR:SBR:PBR (70: 15: 15) tri blend and NR:PBR (70:30) diblend based motorcycle tyre tread base rubber composition.

IN6731/DELNP/2012 relates to a process for forming a compatibilized silica and nitrile polymer blend in latex form. The process can include treating a silica with a coupling agent to form a compatibilized silica slurry. The process can include blending the compatibilized silica slurry into a styrene butadiene polymer latex and an acrylonitrile butadiene polymer latex. The process can include blending silica styrene butadiene polymer latex with silica acrylonitrile butadiene polymer latex. A polymer composition of a compatibilized silica in blends of acrylonitrile butadiene polymer and styrene butadiene polymer and a recycled elastomeric composition are described herein. The recycled elastomeric composition can also include a compatibilized silica with a coupling agent a crumb rubber a carbon black a filler and an extender oil. Articles comprising the recycled elastomeric composition are disclosed herein.

An elastomeric polymer composition with crumb rubber and compatibilized silica whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

INI 171/DEL/2015 provides renewed rubber that can be processed much more easily than conventional recycled rubber compositions. It also consistently exhibits an array of better overall cured rubber properties with only minimal variations in characteristics, by using feed stocks made by various grinding methods. In the chemical functionalization of the renewed rubber compositions of this invention, the sulfur-sulfur bonds in micronized rubber powder are broken to partially devulcanize the rubber, with only a minimal number of carbon-carbon double bonds in the backbone of the polymer being broken. This allows for the renewed rubber of this invention to be used in rubber formulations that are used in manufacturing a wide array of rubber products, including tires, power transmission belts, conveyor belts, hoses, and a wide array of other products. The present invention more specifically discloses a method for manufacturing an environmentally friendly, chemically functionalized, renewed rubber composition having a highly desirable combination of physical properties and which exhibits excellent processability comprising the steps of (1) blending a micronized rubber powder with a processing aid and a chemical functionalizing agent to produce a blended mixture; (2) processing the blended mixture under conditions of high shear and low temperature to produce a reacted mixture; (3) adding a stabilizer to the reacted mixture to produce the chemically functionalized renewed rubber composition. The referred patent discusses about the use of renewed rubber (blending a micronized rubber powder with functionalized agent) in tyre tread and sidewall formulations whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

CN111205569 discloses modified butyl rubber prepared from the following raw materials in parts by weight: 30-50 parts of butyl rubber, 20-30 parts of maleic anhydride, 8-12 parts of phenolic resin 2402, 40-50 parts of carbon black, 2-3 parts of ethylene glycol monobutyl ether, 2-4 parts of ACR resin, 1-3 parts of sulfur, 1-2 parts of a vulcanization accelerator ZDMC, 20-40 parts of butyl reclaimed rubber, 10-20 parts of aramid pulp, 2-4 parts of decabromodiphenyl ether and 50-70 parts of an accelerator TMTD. Aramid pulp is well dispersed in a rubber matrix, has an obvious reinforcing effect on compounding, and can be well dispersed in a rubber material together with compound intercalated mineral powder. The referred patent discusses about modified butyl rubber composition whereas the present invention discusses about the use of recovered carbon black in NR:SBR:PBR tri blend and NR:PBR blend based tread base rubber composition.

CN108102181 relates to a rubber materials and method for preparing reclaimed rubber from waste rubber powder. Waste tires are cleaned up, dried, smashed and sieved, and a product is taken as black rubber powder for standby application; leftover materials of shoe soles are cleaned up, dried, smashed and sieved, and a product is taken as yellow rubber powder for standby application; 50 parts of carbon black, 50 parts of the black rubber powder and 50 parts of the yellow rubber powder are subjected to high-temperature plastication on a plasticator, reclaimed rubber master batch is prepared, the rubber master batch is mixed with zinc oxide, stearic acid, a reclaiming agent and an accelerant, a product is left to stand for 10-20 h, and a rubber compound is prepared; the rubber compound is put in an open mill for vulcanization, the accelerant and sulfur are added, thin-passing triangular bag beating processing is performed 4-7 times, and a finished product is obtained. According to the method, the reclaimed rubber is prepared with a high-temperature reclaiming vulcanization method, the preparation is environmentally friendly, and operation is simple. With the adoption of the preparation method, the utilization rate of waste rubber is increased, industrial rubber garbage is reduced, the reclaimed rubber can meet national or industrial standard, and the method has the advantages of waste utilization, environmental protection, and the like. The referred patent discusses about the method of preparation of reclaim rubber from waste rubber powder whereas the present invention discusses about the use of recovered carbon black in motorcycle tread base rubber composition.

CN107602956 discloses low-cost sidewall rubber compound formula with addition of reclaimed rubber. The rubber compound includes, by weight, 40-60 parts of natural rubber SMR20, 40-60 parts of butadiene rubber BR9000, 40-60 parts of carbon black N330, 20-30 parts of the reclaimed rubber, 3-6 parts of composite active ZnO, 2-5 parts of stearic acid, 0.5-2 parts of an anti-aging agent RD, 1-4 parts of an anti-aging agent 4020, 0.6-2 parts of an anti-aging agent 3100, 1-3 parts of microcrystalline wax, 2-5 parts of tert-butyl tackifying resin, 3-6 parts of aromatic hydrocarbon oil, 1-4 parts of sulfur powder, 0.6-1 part of an accelerant NS, and 0.2-0.5 parts of an anti-coking agent CTP. In the invention, according to a three-stage mixing process, firstly the natural rubber is mixed with a part of the carbon black to reduce the Mooney viscosity of raw rubber; then the reclaimed rubber and the butadiene rubber are mixed with the rest of the carbon black and additives to solve a problem of non-uniform mixing and dispersion due to blend of different rubbers having different Mooney viscosities; finally, premixed first-stage mixed rubber and second-stage mixed rubber and the sulfur powder and the like are mixed to obtain the sidewall rubber compound. The invention also provides the preparation method for the low-cost sidewall rubber compound formula with addition of the reclaimed rubber. The referred patent discusses about the addition of reclaimed rubber in NR: BR blend based tyre sidewall formulation whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition. US 6207723 provides a rubber composition containing a reclaimed rubber and a method for producing the same. A rubber molded article having excellent rubber properties can be obtained and the recycling of a used rubber product can be promoted by the present invention. A rubber composition of the present invention is a blend comprising a claimed rubber obtained by applying a heat and a shear stress to a vulcanized rubber, a non-vulcanized virgin rubber or/and a thermoplastic resin, wherein the reclaimed rubber contains 40% by weight or more of a residual toluene-insoluble gel component and the network chain density of the rubber in the gel component is 1/20 to 1/4 based on the network chain density of the rubber of the vulcanized rubber. The referred patent discusses about a rubber composition containing reclaimed rubber whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

CN105566702 discloses an agricultural tire crown compound of high filling tire reclaimed rubber. The agricultural tire crown compound is prepared from the following raw materials in parts by mass: 25 to 35 parts of standard rubber No.20; 15 to 25 parts of cis-butadiene rubber 9000; 10 to 50 parts of butadiene-styrene rubber 1502; 70 to 30 parts of tire reclaimed rubber; 3.0 to 5.0 parts of zinc oxide; 2.0 to 4.0 parts of stearic acid; 0.5 to 0.7 part of anti-aging agent BLE; 0.8 to 1.0 part of anti-aging agent RD; 1.5 to 2.5 parts of anti-aging agent 4020; 2.0 to 3.0 parts of protective wax; 55 to 65 parts of intermediate super carbon black N220; 9.0 to 12 parts of aromatic hydrocarbon oil; 1.5 to 2.5 parts of sulfur; 1.1 to 1.3 parts of accelerant NOBS; 1.0 to 2.0 parts of thermal oxidation resistant agent RF; 1.0 to 2.0 parts of homogenizing dispersant MS. The agricultural tire crown compound has the advantages that the processability of low-temperature emulsion aggregation of SBR (styrene butadiene rubber) is improved, resource recycling is realized, pollution is reduced, the environment is protected, and the production cost is reduced, etc. The referred patent uses NR:SBR:BR triblend along with reclaimed rubber for tire agricultural tyre crown compound whereas the present invention discusses about the NR:SBR:PBR tri blend and NR:PBR blend along with recovered carbon black for motorcycle tyre tread base rubber composition.

CN103992655 provides a negative ion releasing asphalt -rubber mixture and a preparation method thereof. The negative ion releasing asphalt-rubber mixture is characterized by consisting of the following components according to a formula: 60-100 of asphalt; 0.5-25 of a functional additive; 0-40 of a filler; 0-80 of a polymer; and 0-20 of a curing agent. The polymer is one to three of nitrile rubber, natural rubber, silicon rubber, natural rubber and reclaimed rubber. The additives include a stabilizer, a plasticizer, a crosslinking promoter and an antiager. The functional additive is an Anna O. negative ion additive. The filler is one of or a mixed inorganic compound composed of two or more of mica powder, white carbon black and carbon black. The curing agent is one or two of trithiocyanuric acid, dicumyl peroxide, sulfur and a diamine compound. The negative ion releasing asphalt-rubber mixture provided by the invention aims to play a significant role in low carbon economy and sustainable development through extensive use in the fields of materials, aviation, shipbuilding, automobiles, railways, building and bridges, etc. The referred patent discusses about negative ion releasing asphalt rubber mixture whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

CN101759869 provides a waste vulcanized rubber reclaiming agent composition comprising metal complexing compound and aryl sodium sulfonate formaldehyde condensate (general formula: CH2-(-R' SO3Na) 2, wherein R' is aryls comprising phenyl, naphthyl, anthryl and derivative thereof). The composition further comprises stearic acid, diethylene glycol, triethanolamine, white carbon black, natural rubber or synthetic rubber latex and other auxiliary materials. The composition can effectively and fully leads the cross-bond of waste vulcanized rubber to be cracked under the mechanical action at the normal temperature, and leads the waste vulcanized rubber to be restored into reclaimed rubber which can be recycled. The waste vulcanized rubber reclaiming agent composition is applicable to recycling multiple rubbers such as nature rubber, butadiene styrene rubber, butadiene rubber, butadiene acrylonitrile rubber, chloroprene rubber, butyl rubber, ethylene -propylene-diene monomer (EPDM) rubber, halogenated butyl rubber, etc. In the processing process of preparing the reclaimed rubber, the composition generates no waste gas, waste water and waste material. The reclaimed rubber prepared by the composition has the comprehensive physical and mechanical properties reaching to more than 70% of the original waste vulcanized rubber matrix. The referred patent discusses about waste rubber reclaiming agent composition whereas the present invention discusses about the use of recovered carbon black for motorcycle tyre tread base rubber composition.

JPH 11323004 provides a desulfurizing agent slight in smelling, capable of selectively and efficiently cutting a sulfur crosslinking bond and giving a sufficient desulfurizing effect even to vulcanized rubber, etc., mixed with a filler such as carbon black, a desulfurization using the same agent, and reclaimed rubber containing desulfurized rubber obtained by the desulfurization. Solution: This desulfurizing agent contains a halogenated diphenyl disulfide compound expressed by the formula (R<1> and R<2> are each a halogen atom) and vulcanized rubber can be desulfurized by mixing the desulfurizing agent into vulcanized rubber and heat-kneading. Vulcanized rubber obtained by such a manner is solely used or used after mixing with unvulcanized rubber and vulcanized by adding a vulcanizing agent to obtain reclaimed rubber having physical properties equivalent to usual vulcanized rubber. The referred patent discusses about reclaimed rubber containing desulfurized rubber whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

GB348299 relates to the production of electrical insulating materials having a basis of rubber, limited proportions of carbon black having high absorptive properties are added to improve the electrical properties of the materials. Best results are secured with an amount of carbon black not exceeding approximately 10 per cent by weight on the total rubber content (crude rubber plus the rubber content of any reclaimed rubber in the compound). Several examples are given, one of which contains in parts by weight 409,0 rubber (smoked sheets), 250,0 Champion reclaim (acid-reclaimed rubber), 90,0 zinc oxide, 200,0 mineral rubber, 5,8 antioxidant (agerite), 20,0 carbon black, 1,0 tetramethyl -thiuram- monosulphide, 22,0 sulphur. It is stated that the carbon black may replace zinc oxide in compositions containing it.

The referred patent discusses about the limited proportions of carbon black are added to achieve electrical properties in electrical insulation materials whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition. Both the application and compound design are entirely different from each other.

US9815974 talks about micronized solution styrene -butadiene rubber from postconsumer sources can be included in rubber formulations without severely compromising abrasion resistance. The micronized solution styrene -butadiene rubber utilized in the rubber formulations of this invention can be made by cryogenic grinding postconsumer rubber products using conventional procedures. For instance, it can be made by cryogenically grinding a tire tread containing a high level of solution styrene -butadiene rubber. The micronized solution styrene-butadiene rubber can then be blending into desired virgin rubbers and cured without significantly compromising the abrasion resistance of the rubber formulation. The rubber formulation of this invention is comprised of a natural or synthetic rubber and from 1 weight percent to 30 weight percent of a micronized rubber composition containing at least 10 weight percent solution styrene -butadiene rubber and having a particle size of 40 mesh to 200 mesh. The referred patent discusses about the use of micronized solution styrene butadiene rubber in rubber formulation whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

CA 1052063 talks about vulcanised rubber reclaimed by treating pieces of the rubber to render a surface layer of each piece plastic while the inner core of the piece remains nonplastic. A chemical reagent can be used in the treatment, but it is preferred to render the surface layers of the rubber pieces plastic by a heat treatment which involves direct exposure of the pieces of rubber to either a flame or a heated gas. In a preferred embodiment of the invention vulcanised rubber pieces are dropped under gravity into a flame so that any attached textile residues are burnt away simultaneously with the plasticising of the surface layers of the pieces and the heated pieces then enter a stream of cold air which quenches the heat treatment. Vulcanised rubber articles made from the rubber reclaimed by the method of the invention have improved properties as compared with articles made by the conventional methods of reusing vulcanised rubber. The referred patent discusses about the method of preparing reclaimed rubber to improve the properties whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

US2014116594 provides an inner liner rubber composition that enables improvements in handling stability, fuel economy, elongation at break, sheet processability, air barrier properties, and compounding cost in a balanced manner; and a pneumatic tire including an inner liner formed from the rubber composition. The rubber composition includes: a reclaimed butyl rubber; a halogenated butyl rubber other than the reclaimed butyl rubber; at least one semi -reinforcing filler selected from the group consisting of finely ground bituminous coal, talc, mica, and hard clay; and carbon black having a specific N2SA and/or silica having a specific N2SA, wherein the finely ground bituminous coal has a specific average particle size, and the rubber composition has a predetermined reclaimed butyl rubber content, a predetermined combined content of the reclaimed butyl rubber and the halogenated butyl rubber, a predetermined total semi -reinforcing filler content, and a predetermined combined content of the carbon black and the silica. The referred patent discusses about the use of reclaimed butyl rubber in the inner liner composition to save the cost whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition to save the cost. CN111675835 discloses a natural rubber formula with high adhesive strength. The natural rubber formula with high adhesive strength comprises, by weight, 40 to 50 parts of natural rubber, 60 to 70 parts of reclaimed rubber, 5 to 8 parts of carbon black, 0.8 to 0.9 part of zinc oxide, 0.3 to 0.4 part of stearic acid, 2 to 3 parts of an anti-aging agent, 1.5 to 2.0 parts of a vulcanization accelerator, 1.2 to 1.8 parts of a vulcanizing agent and 0.6 to 1.0 part of a processing aid. The reclaimed rubber is prepared by taking waste steel wire load-bearing outer tire treads as a raw material, crushing, removing impurities, adding an activating agent and activating auxiliary particles, and performing microwave desulfurization, activation and regeneration. The natural rubber formula with high adhesive strength takes natural rubber and reclaimed rubber as main raw materials, the used reclaimed rubber takes waste tires as the raw material and has good compatibility with the natural rubber after being crushed, desulfurized and activated, and a rubber compound prepared by adopting the formula has high adhesive strength. The referred patent discusses about the use of desulfurized reclaimed rubber in NR Formulation and it relates to the technical field of a rubber whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

US2020109265 discloses rubber composition of the present invention comprises a rubber component (A) comprising 30% by mass or more of a natural rubber and a synthetic isoprene rubber in total, at least one (B) selected from the group consisting of a reclaimed rubber and a powdered rubber, and a polyhydric alcohol (C) having 3 or more hydroxyl groups per molecule. The referred patent discusses about the use of reclaimed rubber and a powdered rubber in rubber composition whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

JPS54135834 relates to a reclaimed rubber, by kneading and plasticizing vulcanized rubber powder in the presence of a specific organic compound, e.g. a monoarylhydrazine, as a catalyst under heating in a short time. Constitution: 100 parts by wt. of vulcanized rubber powder, e.g. powder comprising 100 parts by wt. of vulcanized rubber and 10 parts by wt. or less of a reinforcing material, e.g. carbon black or silica, is kneaded and plasticized in the presence of 5 parts by wt. or less of a catalyst of one or more types of compounds selected from the group consisting of a condensate of a monoarylhydrazine and aldehyde or ketone, a thiol, or a monoarylhydrazine under heating to give a reclaimed rubber. 10 parts by wt. or less of a plasticizer, e.g., aromatic process oil, may be used together. The referred patent discloses use of reclaimed rubber with the presence of a monoarylhydrazine as a catalyst whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

US2021087369 relates to tire tread compositions and methods for making. The compositions include a rubber, a rosin ester resin and at least one filler. The rosin ester resin is characterized as having a PAN number of less than 25, an acid number less than 20, a hydroxyl number of less than 30, a combined acid number and hydroxyl value of less than 50. The tire tread composition has a wet grip resistance to rolling resistance indicator ratio ((tan 5 at 0° C.)/tan 5 at 60° C.) higher than a tire tread composition containing a comparable amount of a rosin ester having a combined acid number and hydroxyl value of more than 50.

The referred patent discusses about the use of rosin esters in tyre tread compositions whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

US2018186973 provides pneumatic tires that can achieve both abrasion resistance and low heat buildup properties. The present invention relates to a pneumatic tire including a tread formed from a rubber composition, the rubber composition containing: a rubber component including an isoprene -based rubber and a high-cis polybutadiene rubber having a cis content of 90% by mass or more; one or more types of carbon black; and sulfur, at least one of the one or more types of carbon black being produced from a feedstock oil that has a BMCI value of 150 or less and an aliphatic hydrocarbon content of 30% by mass or more, the BMCI value being calculated from the average boiling point T (°C) and the specific gravity D (60/60°F) relative to water at 60°F according to the equation below, BMCI = 48 , 640 / T + 273 + 473.7 D 456.8. The referred patent discusses about the use of carbon black produced from a feedstock that has a BMCI value of 150 or less in tyre rubber composition whereas the present invention discusses about the use of recovered carbon black produced from waste tyres in motorcycle tyre tread base rubber composition.

US2016017129 relates to a method of functionalizing reclaimed elastomer material. The method involves subjecting particles of the reclaimed elastomer material to shear at temperatures less than 100° C. such that inter-chain bonds of the reclaimed elastomer material are cleaved wherein the particles of the reclaimed elastomer material have a size of 60 mesh or smaller. The reclaimed elastomer material can be subjected to shear in the presence of a modifier which selectively promotes the cleavage of inter-chain bonds in the reclaimed elastomer material. A functionalized reclaimed elastomer material made by a method as described above and an elastomer compound which comprises the functionalized reclaimed elastomer material are also described. The referred patent discusses about the preparation of functionalized reclaimed elastomer material tyre rubber composition whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

US4243561 talks about green strength of elastomers is improved by the addition of semi-crystalline butene polymers selected from the class consisting of polybutene and interpolymers made from 1- butene monomer and at least one monomer selected from the class consisting of alpha-olefins, nonconjugated dienes, and non-conjugated polyenes. The blend composition may also include reclaimed rubber. The semi-crystalline butene polymer is mixed with a desired elastomer such as natural or synthetic cis- 1 ,4-polyisoprene, or a synthetic elastomer made from monomers selected from the class consisting of conjugated dienes having from 4 to 10 carbon atoms, interpolymers of said dienes among themselves or with vinyl substituted aromatic hydrocarbon compounds having from 8 to 12 carbon atoms, or poly alkenylenes. The mixing or blending of the butene polymer and the elastomer may be through conventional methods such as cement mixing or mastication. This patent discloses a blend composition which may include reclaim rubber to improve green strength whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

US4341667 discloses green strength of compositions containing elastomers and/or up to 100 percent of reclaimed rubber is improved by the addition of crystalline or semi -crystalline butene polymers selected from the group consisting of polybutene and interpolymers made from 1 -butene with at least one monomer selected from the group consisting of alpha-olefins, non-conjugated dienes, and nonconjugated polyenes. Although reclaimed rubbers are utilized, an unexpected increase in green strength of an unvulcanized blend is obtained. The reclaimed rubbers utilized in the blend may be those which have been devulcanized by mechanical energy, heat, and/or chemical agents. Additionally, and preferably, the rubbers may be reclaimed through the use of microwave energy. Additionally, the unvulcanized properties of compositions containing 100 percent of scrap rubber which has been reclaimed using microwave energy are significantly improved by adding crystalline or semi -crystalline alpha-olefin polymers, such as polyethylene or polypropylene. Unexpected improvements in solvent resistance and molding properties of the uncured blends are also achieved. The referred patent discusses about the use of reclaimed rubber to improve green strength whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

US 10513600 relaters to elastomer compositions comprising uncured elastomer and reclaimed elastomer are described. In one embodiment, the compositions comprise reclaimed elastomer material (micronized rubber powder) of broad particle size distribution, which is less expensive than traditional reclaimed elastomer material with narrow particle size distribution. Further, compositions comprising reclaimed elastomer materials with broad particle size distribution perform comparably to those comprising reclaimed elastomer materials with narrow particle size distribution. In other embodiments, the compositions comprise both vulcanized and devulcanized elastomer materials. Advantageously, by using a combination of vulcanized and devulcanized material, it is possible to incorporate a greater percentage by weight of reclaimed material into an elastomer composition, thus providing additional cost savings while maintaining high levels of mechanical properties. Further, the use of the reclaimed material reduces landfill waste resulting in a more environmentally friendly product. The referred patent uses micronized rubber powder in elastomer composition to provide cost savings whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition to provide cost savings.

US 8076404 relates to rubber compositions containing a filler and comprising (i) at least one rubber containing olefinic unsaturation and (ii) functionalized nano transition metal oxide and/or sulfide particles. The invention further relates to a method of manufacture of the rubber compositions and to the use of the compositions in tires, belts and/or hoses. This patent discloses use of functionalized nano zinc oxide and/or nano zinc sulfide particles in rubber composition whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition to provide cost savings.

US9574069 talks about renewed rubber used in rubber formulations that are used in manufacturing a wide array of rubber products, including tires, power transmission belts, conveyor belts, hoses, and a wide array of other products. The present invention more specifically discloses a method for manufacturing an environmentally friendly, chemically functionalized, renewed rubber composition having a highly desirable combination of physical properties and which exhibits excellent processability comprising the steps of (1) blending a micronized rubber powder with a processing aid and a chemical functionalizing agent to produce a blended mixture; (2) processing the blended mixture under conditions of high shear and low temperature to produce a reacted mixture; (3) adding a stabilizer to the reacted mixture to produce the chemically functionalized renewed rubber composition. This patent discloses use of micronized rubber powder produced with a chemical functionalizing agent in rubber formulations whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

US2015283774 relates to a method of making a tire tread includes mixing a tire tread compound including a virgin rubber component and a reclaimed rubber component, forming a green sheet from the tire tread compound, and curing the green sheet to form a cured tire tread. The reclaimed rubber component may have a Mooney viscosity (ML (1+4) @ 100° C.) of greater than 65. The reclaimed rubber component may also have a crosslink density that is between 20% and 50% of the crosslink density of the reclaimed rubber prior to reclaiming. The referred patent discusses about the use of reclaimed rubber component forming a green sheet from the tire tread compound whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

US2014228505 relates to the curable elastomer compositions which include particles of reclaimed elastomeric material having a particle size of 60 mesh or smaller, sulfur and one or more accelerators, wherein the ratio by weight of the one or more accelerators to sulfur in the composition is at least 1: 1. Curable styrene butadiene rubber (SBR) elastomer compositions are also described which include reclaimed elastomeric material, sulfur and one or more accelerators, wherein the ratio by weight of the one or more accelerators to sulfur in the composition is at least 1:1. The cured elastomeric compositions exhibit improved physical properties compared to elastomer compositions containing reclaim material which employ conventional high sulfur cure systems. This patent refers to use of reclaimed elastomeric material in rubber compositions whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

US2014110031 relates to a rubber composition for an inner-liner joint strip is capable of improving green strength and adhesion, while maintaining good durability (oxidative degradation resistance, crack growth resistance) and good air retention properties, which are exhibited by a pneumatic tire formed from the composition. The rubber composition for an inner-liner joint strip, includes: a butyl rubber; silica and/or carbon black; and an alkylphenol-sulfur chloride condensate represented by formula (1) below, wherein a butyl rubber content is 60 to 100 mass % based on 100 mass % of the rubber component of the rubber composition, a total combined amount of the silica and the carbon black is 21 to 70 parts by mass per 100 parts by mass of the rubber component, and an amount of the alkylphenol- sulfur chloride condensate is 0.1 to 5 parts by mass per 100 parts by mass of the rubber component. This patent discusses use of alkyl phenol sulfur chloride condensate in innerliner joint strip rubber compositions whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition.

US2010292383 relates to a carrier elastomer composition having an elastomer material between about 20% to about 80% by weight of the carrier elastomeric composition. The carrier elastomeric composition also includes a fine agglomerates mixture of filler derived from pyrolyzed polymeric materials. The fine agglomerates mixture of filler comprises between about 10% to about 70% by weight of the carrier elastomeric composition. The carrier elastomeric composition also has a processing oil that is present in a quantity of about 25% to about 30% by weight of the carrier elastomeric composition. The carrier elastomeric composition in accordance with the present invention serves as a carrier for transporting the fine agglomerates mixture which includes agglomerate having an average particle size equal to or less than 35 nm. This patent uses pyrolyzed carbon black in SBR and EPDM based elastomeric compositions whereas the present invention discusses about the use of recovered carbon black (rCB) in NR:SBR:PBR (70:15: 15) tri blend and NR:PBR (70:30) motorcycle tyre tread base composition. Both the rubber compositions are totally different from each other.

CN106674777 relates to an inner liner compound and a preparation method thereof. The inner liner compound comprises the following components in parts by weight: 80-100 parts of brominated butyl rubber, 40-50 parts of butyl reclaimed rubber, 5-15 parts of graphene/graphene oxide natural rubber compound master batches, 55-70 parts of carbon black, 0.5-0.7 part of stearic acid, 5.0-7.0 parts of aromatic hydrocarbon, 9.0-12.0 parts of a homogenizing agent, 5.0-7.0 parts of C5 petroleum resin, 0.5-0.7 part of sulfur powder, 1.5-2.0 parts of an accelerant and 1.0-1.25 parts of zinc oxide. The preparation method successively comprises the steps: plastifying; mixing in a first section; standing at the first time; and finally mixing to obtain an inner liner compound product. The preparation method provided by the invention is simple and easy to operate steps, the prepared inner liner compound is low in gas permeability, and the gas barrier property is improved. This patent discusses use of butyl reclaimed rubber and graphene/graphene oxide masterbatch in an innerliner compound whereas the present invention discusses about the use of recovered carbon black (rCB) in NR:SBR:PBR (70:15:15) tri blend and NR:PBR (70:30) blend based motorcycle tyre tread base composition. Both the rubber compositions are totally different from each other.

CN105001533 discloses a modified butyl rubber material for automobile inner tube, which is prepared by using the following raw materials in parts by weight: 30-50 parts of butyl rubber; 20-30 parts of EPDM; 8-12 parts of phenolic resin 2402; 40-50 parts of carbon black; 2-3 parts of N'-xylyl p- phenylenediamine; 2-4 parts of ACR resin; 1-3 parts of sulphur; 1-2 parts of vulcanization accelerator ZDMC; 20-40 parts of butyl-reclaimed rubber; 10-20 parts of pulp of phenylene terephthalamid; 2-4 parts of cashew nut shell oil; and 50-70 parts of compound intercalating modified powder. The pulp of phenylene terephthalamid may be well dispersed in a rubber matrix, has an obvious enhancement effect on a composite material, and can be well dispersed in a glue stock with compound intercalating mineral powder. This patent discusses use of butyl reclaimed rubber in an automobile inner tube whereas the present invention discusses about the use of recovered carbon black (rCB) in motorcycle tyre tread base composition. Both the rubber compositions are totally different from each other.

US5425904 relates to a process for activating vulcanized waster rubber particles by treating the waste rubber particles with a rubber latex and a curing system and drying the treated waste rubber particles. The waste rubber particles are preferably treated with 1 to 4% by weight of rubber latex (calculated as dry substance) and 0.5 to 3% by weight of sulfur as vulcanizing agent, both being calculated on the waster rubber particles. The treatment is carried out conveniently by mixing the waste rubber particles with the vulcanizing agent, adding the latex at a temperature of from 70 DEG to 90 DEG C. and stirring the obtained mixture for 5 to 10 min. so as to evaporate the water. Also disclosed are processes for producing a rubber-like article by molding the activated waste rubber particles, whether or not mixed with a non-vulcanized rubber compound, while applying heat and pressure. This patent discusses use of treated waste rubber particles in non-vulcanized rubber compound whereas the present invention discusses about the use of recovered carbon black (rCB) in motorcycle tyre tread base composition. US2013048169 relates to a tread for a pneumatic tire includes a tread base layer, a first tread cap layer radially outside of the tread base layer, a second tread cap layer radially outside of the tread base layer and both radially outside and axially adjacent the first tread cap layer, a first tread skirt disposed at an inner tread edge of the pneumatic tire and axially adjacent the tread base layer and the first tread cap layer, and a second tread skirt disposed at an outer tread edge of the pneumatic tire and axially adjacent the tread base layer and the second tread cap layer. This is dual tread cap pneumatic tire. Rubber composition containing conjugated diene rubbers along with carbon black/silica (carbon black which is used is not produced from waste tyre) in dual tread cap whereas the present invention discusses about the use of recovered carbon black (rCB) which is produced from waste tires in NR:SBR:PBR (70: 15: 15) tri blend and NR:PBR (70:30) blend motorcycle tyre tread base rubber composition. Both the fillers are totally different from each other.

US2015360514 discloses a tire having crack resistant sidewalls which include a micronized rubber powder. These tires are comprised of a generally toroidal-shaped carcass with an outer circumferential tread, two spaced beads, at least one ply extending from bead to bead and sidewalls extending radially from and connecting said tread to said beads, wherein said tread is adapted to be ground-contacting, and wherein the sidewalls are comprised of 20 phr to 80 phr of natural rubber, 20 phr to 80 phr of polybutadiene rubber, and 3% over batch weight to 20% over batch weight of micronized rubber powder, wherein the micronized rubber powder has a particle size which is within the range of 40 Mesh to 300 Mesh. The referred patent discusses about crack resistant sidewall rubber compound using micronized rubber powder whereas the present invention discusses about the use of recovered carbon black (rCB) which is produced from waste tires in NR:SBR:PBR (70:15:15) tri blend and NR:PBR (70:30) blend based motorcycle tyre tread base rubber composition.

CN102838785 relates to tyre, which comprises the following raw and auxiliary material components by weight: a, carcass ply compound: 1900-3000 of natural rubber, 750-1000 of butylbenzene rubber, 5700-7700 of calcium carbonate, 50-75 of sulphur, 120-200 of zinc oxide, 250-350 of titanium dioxide, 2-4 of stearic acid, 6-8 of accelerant M and 50-80 of accelerant DM; b. tread rubber: 1000-2000 of natural rubber, 3500-4500 of reclaimed rubber, 45-70 of sulphur, 3000-4000 of calcium carbonate, 500-700 of carbon black, 40-70 of resin, 100-150 of zinc oxide, 100-250 of white mineral oil, 30-50 of stearic acid, 6-8 of accelerant M and 20-30 of accelerant DM. The manufacturing method of the tyre comprises the following steps: a, refining rubber; b, extruding tread; c, jointing and molding; and d, vulcanizing. By adopting the tyre and the manufacturing method thereof, rubber tyres of baby carriers and bicycles stably achieve present European standard (mainly the sum of 16 items of PAHS is less than or equal to 200 mg/kg), the technical barrier of Europe and America is broken, and the product can enter the markets of Europe and America. This patent provides choice of raw materials from different components of tyre to achieve PAHS is less than or equal to 200mg/Kg whereas the present invention discusses about the use of recovered carbon black (rCB) in motorcycle tyre tread base rubber composition.

CN 107141621 discloses a thermal aging resistant improved formula of a butyl tube compound, and the formula comprises the following components in parts by weight: 80-90 parts of butyl rubber, 20-40 parts of ethylene -propylene-diene monomer masterbatch, 50-60 parts of butyl reclaimed rubber, 60-70 parts of carbon black, 15-20 parts of paraffin oil, 3-5 parts of zinc oxide, 1-3 parts of stearic acid, 1-2 parts of microcrystalline wax, 0.8-1.5 parts of sulfur, 0.8-1 part of an accelerator M and 1.5-2 parts of TT, wherein the formula of the ethylene -propylene-diene monomer masterbatch comprises the following components in parts by weight: 100 parts of ethylene -propylene-diene monomer, 20-30 parts of white carbon black, 30-50 parts of carbon black and 20-25 parts of paraffin oil. According to the improved formula of the butyl tube compound disclosed by the invention, the ethylene -propylene-diene monomer and the white carbon black are subjected to mixed dispersion previously, and the butyl tube compound can effectively improve the thermal aging resistance of a tube, maintain good physical properties and operating characteristics for the tube at high temperature, and prolong the service life of the tube at high temperature. The referred patent discusses about butyl reclaimed rubber whereas the present invention discusses about the use of recovered carbon black (rCB) in motorcycle tyre tread base rubber composition.

US2020079935 relates to a rubber composition comprising a blend based on 100 parts by weight (phr) of diene elastomers: 5 to 95 phr of a first diene elastomer, 5 to 50 phr of a hydrogenated styrenic block copolymer (HSBC), 50 to 200 phr of a filler, up to 25 phr of a plasticizer. The HSBC has a melt flow ratio of 1.0 to 50.0 measured according to ASTM D-1238 at 230° C. and 2.16 kg load, a Shore A hardness of 40 to 80 measured according to ASTM D-2240, a DMA peak tan delta temperature of 0° C. to 40° C. at 1 Hz measured according to ASTM D-4065, and an order-disorder transition temperature of 200° C. to 300° C. The composition does not comprise a resin, a plasticizer, or comprises a resin or a plasticizer in an amount of less than 20 phr. The referred patent discusses about use of hydrogenated styrene block copolymer in rubber composition whereas the present invention discusses about the use of recovered carbon black (rCB) in motorcycle tyre tread base rubber composition.

US2019055383 relates to crumb rubber obtained from recycled tires which is subjected to an interlinked substitution process. The process utilizes a reactive component that interferes with sulfur bonds. The resulting treated rubber exhibits properties similar to those of the virgin composite rubber structure prior to being granulated, and is suitable for use in fabricating new tires, engineered rubber articles, and asphalt rubber for use in waterproofing and paving applications. This patent uses crumb rubber obtained from recycled tyres in different rubber article applications whereas the present invention discusses about the use of recovered carbon black (rCB) from waste tyres in motorcycle tyre tread base rubber composition. Both the applications are totally different from each other.

US2019023083 provides a pneumatic tire in which an electric resistance can be reduced without adversely affecting other performances such as tire durability or manufacturing processes even when low loss of a rubber member of the tire is attempted. The pneumatic tire includes a belt layer 2 provided at an outer side of a crown portion of a carcass 1 in a tire radial direction, and a rubber chafer 4 is provided at an outer surface of a bead portion in a tire width direction. A cushion rubber 13C and a tread rubber 13G are sequentially provided at an outer side of the belt layer in the tire radial direction, and a composite fiber 3 containing a conductive fiber and a non -conductive fiber extends at least from the bead portion to a position in contact with the cushion rubber or a belt under cushion arranged at an outer end portion of the belt layer in the tire width direction in such a manner as to be exposed on at least one surface the carcass at either the outer and inner sides of the tire, and the rubber chafer contains a carbon black having a nitrogen adsorption specific surface area of 30 to 43 m2/g. This patent uses carbon nanotube in chafer rubber composition whereas the present invention discusses about the use of recovered carbon black (rCB) from waste tyres in motorcycle tyre tread base rubber composition.

US2016347926 relates to a method is provided for preparing a reprocessed rubber from thermoset rubber particles. The method comprises the steps of: providing a plurality of thermoset rubber particles; inducing dynamic swelling and dynamic compatibilization of the plurality of rubber particles; admixing at least one de-linking agent with the swelled and wetted rubber particles; and wherein the method is further characterized in that the step of admixing the at least one de-linking agent is carried out under thermo-mechanical mixing. This patent discloses preparation of a reprocessed rubber from thermoset rubber whereas the present invention discusses about the use of recovered carbon black (rCB) in motorcycle tyre tread base rubber composition.

US2010170606 provides a rubber composition improving the uniformity of a butyl rubber gauge and being superior in air permeability resistance (air retaining property), when a tire is molded, by a procedure capable of reducing the fluctuation of the butyl rubber gauge, namely, controlling the property of an unvulcanized rubber, and a tire having the inner liner comprising it. The present invention relates to a pneumatic tire having an inner liner comprising a rubber composition for a pneumatic tire in which the Mooney viscosity measured at 130° C. of an unvulcanized rubber of the rubber composition for a pneumatic tire comprising a butyl rubber is at least 45, wherein the average value and standard deviation of the butyl rubber gauge of shoulder portion of a finished tire satisfy: (Standard Deviation of Butyl Rubber Gauge )/( Average value of butyl rubber gauge) ^0.060. This patent refers to an inner liner butyl rubber composition whereas the present invention discusses about the use of recovered carbon black (rCB) in motorcycle tyre tread base rubber composition.

US2015107735 relates to a tread for a pneumatic tire in accordance with the present invention includes a tread base layer, a first tread cap layer radially outside of the tread base layer, a second tread cap layer radially outside of the tread base layer and both radially outside and axially adjacent the first tread cap layer, a third intermediate layer radially between the tread base layer and the first and second tread cap layers. The first tread cap layer has a protrusion extending radially inward and into the third intermediate layer more than a main body of the first tread cap layer and the second tread cap layer thereby allowing the first tread cap layer to provide the overall tread with enhanced performance characteristics after the main body of the first tread cap layer and the second tread cap layer have worn away. This patent refers to a multi tread cap construction (3 layer construction) whereas the present invention discusses about the use of recovered carbon black (rCB) in motorcycle tyre tread base rubber composition.

US2011297285 relates to a tire rubber composition comprising a rubber compound and a processing oil, wherein the processing oil comprises a modified tall oil pitch, methods of making tires from such compositions, and tires comprising such compositions. This patent discusses use of tall oil pitch in rubber composition whereas the present invention discusses about the use of recovered carbon black (rCB) in motorcycle tyre tread base rubber composition. US4532291 relates to a bead filler rubber composition, comprising: (A) a resin forced rubber composition comprising vulcanizable rubber including 5 to 100 parts by weight, based on 100 parts by weight of the rubber, of fine short fibers of thermoplastic polymer having groups buried therein, and the vulcanizable rubber and the thermoplastic polymer being grafted to each other through a phenol formaldehyde resin pre-condensate at an interface of the fiber; (B) a diene rubber; and (C) carbon black, wherein the following conditions (i) through (iv) are satisfied: (i) the amount of said thermoplastic polymer is 2 to 20 parts by weight based on 100 parts by weight of the total amount of the rubber constituents; (ii) the ratio of the rubber is such that the total amount of the natural rubber or polyisoprene in the component (A) and the component (B) is 100 to 55% by weight; (iii) the amount of the carbon black is 50 to 70 parts by weight on 100 parts by weight of the total amount of the rubber constituents; and (iv) the vulcanizate derived from the rubber composition has a 50% modulus of at least 30 kg/cm2.

The referred patent discusses about the use of fine short fibers of thermoplastic polymer in rubber composition whereas the present invention discusses about the use of recovered carbon black (rCB) in motorcycle tyre tread base rubber composition.

IN201941016936 discloses WTR rubber manufactured by known polymer composition having glass transition temperature (Tg) in the range of -32 to -35°C and having the Polymer 1/Polymer 2/Carbon Black /Low Boiling materials/Ash in the proposition (%) of47-49/13-17/19-22/9-l 1/5-7 respectively. The input waste material is characterized with the known polymer composition range of Tg and polymer / filler / Carbon black / Low boiling matter composition. This will enable the consistent rubber compound composition in addition to uniform cure kinetics. The rubber compound mixed along with WTR rubber as per the mentioned process will have the Min. 4.5 mins of Mooney Scorch T5. The uniform cure kinetics will render the better processing and better cure characteristic of the products manufactured by the waste material mentioned in the above process / method.

This patent refers to use of whole tyre reclaim in rubber composition whereas the present invention discusses about the use of recovered carbon black (rCB) in motorcycle tyre tread base rubber composition. US9254715 the invention provides an inner liner rubber composition that enables improvements in handling stability, fuel economy, elongation at break, sheet processability, air barrier properties, and compounding cost in a balanced manner; and a pneumatic tire including an inner liner formed from the rubber composition. The rubber composition includes: a reclaimed butyl rubber; a halogenated butyl rubber other than the reclaimed butyl rubber; at least one semi -reinforcing filler selected from the group consisting of finely ground bituminous coal, talc, mica, and hard clay; and carbon black having a specific N2SA and/or silica having a specific N2SA, wherein the finely ground bituminous coal has a specific average particle size, and the rubber composition has a predetermined reclaimed butyl rubber content, a predetermined combined content of the reclaimed butyl rubber and the halogenated butyl rubber, a predetermined total semi -reinforcing filler content, and a predetermined combined content of the carbon black and the silica.

This patent discusses about the use of reclaimed butyl rubber in the inner liner composition to save the cost whereas the present invention discusses about the use of recovered carbon black in motorcycle tyre tread base rubber composition to save the cost.

Thus the rubber products waste disposal after the end of the life is very challenging one. These rubber products are recycled and used in several methods. Reclaim process is a method used for many years to get reclaim rubber. Now, the recovered carbon black (rCB) obtained from end of life tyres through pyrolysis process is being used presently in different rubber vulcanizate but there still needed a rubber composition which can provide tyres with better performance.

In order to overcome above listed prior art, the present invention aims to provide the motorcycle tyre tread base rubber composition using recovered carbon black and its method thereof. The use of recovered carbon black (rCB) derived from end -of- life tyres in NR: SBR: PBR (70:15:15) tri blend and NR:PBR (70:30) motorcycle tyre tread base rubber composition.

OBJECTS OF THE INVENTION:

The principal object of the present invention is to provide motorcycle tyre tread base rubber composition using recovered carbon black. Another object of the present invention is to provide motorcycle tyre tread base rubber composition using recovered carbon black and its method thereof.

Yet another object of the present invention is to provide motorcycle tyre tread base rubber composition using recovered carbon black providing lower Mooney viscosity.

Yet another object of the present invention is to provide motorcycle tyre tread base rubber composition using recovered carbon black providing high rubber elasticity.

Yet another object of the present invention is to provide motorcycle tyre tread base rubber composition providing lower rolling resistance.

Still another object of the present invention is to provide motorcycle tyre tread base rubber composition with lower Payne effect along with better rubber processing properties.

Yet another object of the present invention is to provide cost benefits.

Yet another object of the present invention is to reduce the size of the carbon footprint.

SUMMARY OF THE INVENTION

One or more problems of the conventional prior arts may be overcome by various embodiments of the present invention.

It is primary aspect of the present invention to provide a rubber composition for tyre tread base, comprising: elastomeric blends- 100 phr; reinforcing filler - 30 - 45 phr; recovered carbon black (rCB) - 5- 20 phr; cure activators- 1.50 - 4 phr; process aid - 10 phr; anti-degradants - 1- 2.50 phr; vulcanizing agent - 2.20 phr; and accelerator - 0.40 phr, wherein the composition comprises of recovered carbon black having the iodine adsorption number (surface area) value ranges from 75 to 90 mg/gm, DBP absorption number value ranges from 100 to 120 cc/100 gm and SiCh content ranges from 8 to 11%, as reinforcing filler.

It is another aspect of the present invention to provide the rubber composition for tyre tread base, wherein the elastomeric blend is selected from tri-blend of natural rubber, non-oil extended emulsion polymerized styrene butadiene rubber and poly butadiene rubber, or di -blend of natural rubber and polybutadiene rubber.

It is another aspect of the present invention to provide the rubber composition for tyre tread base, wherein the elastomeric blend comprises of natural rubber, non-oil extended emulsion polymerized styrene butadiene rubber and butadiene rubber in a weight ratio of 70: 15: 15.

It is another aspect of the present invention to provide the rubber composition for tyre tread base, wherein the elastomeric blend comprises of natural rubber, and poly butadiene rubber in a weight ratio of 70:30.

It is another aspect of the present invention to provide the rubber composition for tyre tread base, wherein the reinforcing filler is carbon black.

It is another aspect of the present invention to provide the rubber composition for tyre tread base, wherein the cure activator comprises zinc oxide and stearic acid, in a weight ratio of 2.50: 1.50.

It is another aspect of the present invention to provide the rubber composition for tyre tread base, wherein the process aid is selected from one of aromatic oil, MES oil and TDAE oil.

It is another aspect of the present invention to provide the rubber composition for tyre tread base, wherein the anti-degradants comprise MC (microcrystalline) wax and 6PPD (N-(l,3-dimethylbutyl)- N’ -phenyl -p-phenylenediamine), in a weight ratio of 1:1.50. It is another aspect of the present invention to provide the rubber composition for tyre tread base, wherein the vulcanizing agent is sulphur.

It is another aspect of the present invention to provide the rubber composition for tyre tread base, wherein the accelerator is CBS (N-cyclohexyl-2-benzothiazolesulfenamide).

It is another aspect of the present invention to provide the rubber composition for tyre tread base, wherein the rubber composition provides lower rolling resistance and the tan delta at 60 deg. C value ranges from 0.137 to 0.150.

It is another aspect of the present invention to provide a process of preparation of rubber composition for tyre tread base, comprising of steps:

Preparation of master batch: the parameters for mixing include rotation speed of the mixer between 45 and

60 rpm and with the head temperature of the Banbury mixer maintained between 85 and 100 deg. Celsius, mixing of the polymers for 10 - 30 seconds; addition of 100% reinforcing filler (30 - 45 phr) N220 carbon black or N330 Carbon Black (30 -45 phr) and 5-20 phr of the recovered carbon black (rCB) along with aromatic oil, rubber chemicals 6PPD (N-(l,3-dimethylbutyl)-N’ -phenyl -p- phenylenediamine), MC wax, stearic acid, and zinc oxide, and allowed to mix for 160- 240 seconds; sweeping down in an orifice and allowed to mix for 60 to 90 seconds and the rubber compound has been dumped and sheeted out in laboratory two roll mill,

Preparation of final batch: the parameters for mixing include rotation speed of the mixer between 45 and 60 rpm and with the head temperature of the Banbury maintained between 80 and 100 deg. Celsius; and mixing chamber charged with the master batch compound and the curatives sulphur and CBS are added and allowed to mix for 80 to 90 seconds and dumped and sheeted out using laboratory two-roll mill, wherein the polymers are selected from tri-blend of natural rubber, non-oil extended emulsion polymerized styrene butadiene rubber and butadiene rubber in a weight ratio of 70: 15:15, or di-blend of natural rubber and poly butadiene rubber in a weight ratio of 70:30, and wherein the composition comprises of recovered carbon black as reinforcing filler having the iodine adsorption number (surface area) value ranges from 75 to 90 mg/gm and DBP absorption number value ranges from 100 to 120 cc/100 gm and SiC content ranges from 8 to 11%.

DETAILED DESCRIPTION OF THE INVENTION

A tyre tread can be made up of a single or several compounds. When more compounds are used, each compound is designed with specific properties to perform in an efficient manner in terms of manufacture and in actual use during service of the tyre. A typical multi-compound tread can be classified into two parts - a cap part (that meets the road) and the base part (that does not meet the road but is sandwiched between the cap and the tyre carcass or casing). The present invention is applicable for the motorcycle tyre comprising a tread rubber composition having two-layer structure consisting of a cap layer rubber composition and a base layer rubber composition. Also, the tread base layer composition is the bridge between tread cap layer rubber composition and to the carcass rubber composition.

The tread cap is in direct contact with road and it’s typically made with an abrasion-resistant and higher-grip rubber compound and lower rolling resistance. Partial replacement of Recovered carbon, rCB with ASTM carbon grade usage is limited in tread cap rubber composition due to its poor abrasion resistance.

The tread base is the essential part because it creates a bonding between the tread and tire carcass and the tread base can work along with tread cap to provide low rolling resistance.

Hence, the present invention relates to a motorcycle tyre tread base rubber composition using recovered carbon black and its method thereof. The said tread base rubber composition, capable of providing lower Payne effect, lower rolling resistance along with better rubber processing properties and also to provide cost benefits. The rubber composition of tyre tread base rubber composition includes 100 parts by weight of a rubber; with the tri blend of natural rubber (RSS 3), non-oil extended emulsion polymerized styrene butadiene rubber (SBR 1502) and poly butadiene rubber (PBR 1220) or natural rubber (RSS 3) and poly butadiene rubber blend (PBR 1220) diblend; 5 to 20 phr replacement of a recovered carbon black having the iodine adsorption no. (surface area) value ranges from 75 to 90 mg/gm and DBP absorption no. value ranges from 100 to 120 cc/100 gm, SiCh content ranges from 8 to 11 % and, along with conventional carbon black N220 or N330 grade; 10 phr of aromatic oil or MES oil or TDAE Oil, activator system zinc oxide and Stearic acid, anti-ozonant MC Wax (Microcrystalline wax), antidegradant 6PPD, primary accelerator CBS and vulcanizing agent Sulphur.

Method of preparing recovered carbon black:

Through a thermal process under the exclusion of oxygen (Pyrolysis) the used tyres are processed. At the end of the process carbon containing residue remains and it is called as recovered Carbon Black rCB.

Table 1: Rubber compositions 1. RSS 3 from R1 International private limited, Cochin.

2. PBR1220 from Saudi Basic Industries Corporation, SABIC Asia Pacific Pvt Ltd., Singapore.

3. ASTM Grade N220 - ASTM Grade N220 from Birla Carbon, India. It is the reinforcing filler ISAF, Intermediate Superior Abrasion Furnace having the Iodine adsorption No. 116 to 126 mg/gm, tinting strength value between 110 to 129 % ITRB.

4. Recovered Carbon Black, rCB (CCR) from Capital Carbon, India. It is having the iodine adsorption No. (surface area) value ranges from 75 to 90 mg/gm and DBP absorption no. value ranges from 100 to 120 cc/lOOgm.

5. Zinc oxide from POCL Enterprises Limited, India. It is a cure activator added to the rubber compound to activate sulphur vulcanization.

6. Stearic acid from 3F Industries Ltd., India. It is used as a Process aid. Also, Zinc oxide and Stearic acid are added to form zinc soap, improves the solubility of zinc oxide in the compound, and with the accelerator to form a complex, this complex reacts with sulphur to produce a strong cure activating system.

7. Aromatic Oil from Indian Oil Corporation Limited, India.

8. MC Wax (Microcrystalline wax) from Mahatha petroleum private Limited, India. It is used to protect against degradation by ozone.

9. 6PPD, an anti-degradant (N-(l,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine) from Nocil Limited, India. It is added to the rubber composition to provide resistance to thermo -oxidative ageing of elastomers.

10. Sulphur is the vulcanizing agent from The Standard Chemical Co. Pvt Ltd, India.

11. CBS N-cyclohexyl-2-benzothiazolesulfenamide) from Nocil Limited, India. It is a delayed action accelerator suitable for diene rubbers.

Table 2: Rubber compositions

1-11 ingredients mentioned in Table 2 are as mentioned in Table 1.

12. SBR 1502 is from Reliance Industries Limited, Hazira.

13. ASTM Grade N330 - ASTM Grade N330 from Birla Carbon, India. It is the reinforcing filler HAF, High Abrasion Furnace having the Iodine adsorption No. 76 to 86 mg/gm, tinting strength value between 98 to 108 % ITRB.

Method of preparation of rubber composition according to the present invention

The method of preparation of the rubber compositions for Table 1 and 2 is as mentioned below. The rubber composition is prepared using a Banbury mixer with the tangential rotor by a thermo mechanical process as per the following conditions and mixing sequences:

Preparation of master batch:

Preparation of master batch has been performed with the rotation speed of the mixer between 45 to 60 rpm and with the head temperature of the Banbury maintained between 85 to 100 deg. Celsius. a) Mixing chamber has been charged with the polymers, and allowed to mix for 10 to 30 seconds b) Further by adding 100% (30-45 phr) of reinforcing filler N220 carbon black or N330 carbon Black (30 -45 phr) and 5 to 20 phr of the recovered carbon black (rCB) and along with aromatic oil, rubber chemicals 6PPD, MC wax, stearic acid and zinc oxide are added, and allowed to mix for 160 to 240 seconds c) sweeping down in the orifice and allowed to mix for another 60 to 90 seconds and the rubber compound has been dumped. The rubber compound has been sheeted out in the laboratory two-roll mill.

Preparation of Final batch

Preparation of final batch has been performed with the rotation speed of the mixer between 45 to 60 rpm and with the head temperature of the Banbury maintained between 80 to 100 deg. Celsius. Mixing chamber charged with the master batch and the curatives Sulphur and CBS are added and allowed to mix for 80 to 90 seconds and dumped. Final sheet out of the rubber compound has been done in the laboratory two roll mill.

Results:

Characterization of Cured Rubber Vulcanizate and Uncured Rubber Compound:

The Rubber compound properties are listed in Table 3 & 4 below-Measurements and Tests:

The purpose of these tests is to measure the improved properties of the rubber compositions related to the invention against control rubber composition. For this, ten motorcycle tyre tread base rubber compositions Cl, Fl to F4, C2 and F5 to F8 are prepared.

NR: BR blend (70 phr: 30 phr) based motorcycle tyre tread base rubber composition reinforced by N220 carbon black is replaced with 5 to 20 phr of recovered carbon black (Fl to F4- Formulation related to invention) against NR:BR (70 phr: 30 phr) blend reinforced by N220 carbon black (Cl - Control) are prepared and evaluated.

Also, NR:SBR:BR blend (70 phr: 15 phr: 15 phr) based motorcycle tyre tread base rubber composition reinforced by N330 carbon black is replaced with 5 to 20 phr of recovered carbon black (F5 to F8- Formulation related to invention) against NR: SBR: BR (70 phr: 15 phr: 15 phr) blend reinforced by N330 carbon black (C2 - Control) are prepared and evaluated.

M 1 : Better processability (Process Requirements) of a Rubber Compound: a) Masterbatch Mooney viscosity ML (1+4) @ 125 °C for Processability. b) Mooney Scorch Characteristics (pre vulcanization characteristics using large rotor) for processability.

MV indicates the minimum viscosity, ts indicates the time to scorch (MV+5) which indicates the processing properties (process safety).

Both Master batch Mooney Viscosity and Final Batch Mooney Scorch measurements are carried out with a Mooney Viscometer (MV 2000 Alpha technologies, USA) according to ASTM DI 646.

M2. Visco Elastic Properties of a Rubber Vulcanizate: a. Rebound Resilience percentage of a cured rubber vulcanizate is measured using Rebound Resilience tester (Schob type Rebound Pendulam) from Zwick Roell 5109 Rebound resilience tester in accordance with ASTMD 7121. Higher the Rebound resilience % value is higher the rubber elasticity. b. Dynamic Properties of the Rubber Vulcanizate:

The dynamic properties of the rubber vulcanizate are measured on a dynamic mechanical analyzer (DMA Metravib +1000) with a Static Strain: 0.6%, Dynamic Strain: 3%, Temp Sweep: -40 to +80°C, Frequency: 10Hz in tension mode as per ASTM D5992.

Tan delta at 60°C is commonly used as a predictor of rolling resistance. Also, lower the tan delta value at 60°C infers lower rolling resistance. c. Payne Effect.

The RPA (Rubber Process Analyzer) is a dynamic mechanical rheological tester to analyze unvulcanized (uncured) compounds.

The Payne effect is an effective way of studying deagglomeration of fully reinforcing carbon black during the rubber compound mixing process. It should be an effective way of relating to carbon black aggregate — aggregate attraction vs. the carbon black aggregate attraction to the specific rubber hydrocarbon medium.

The Payne effect is the difference in storage modulus (G’) at relatively low elongation rates. The difference (G’@0.7% - G’ @ 10%) is caused by 'filler-filler interaction'. During mixing, the filler should be dispersed homogeneously through the compound, which indicates a break-up of agglomerates into primary particles, resulting in a filler network within the polymer network. Lower the difference (G’@0.7% - G’ @ 10%) value is lower the Payne effect which implies lower filler- filler interaction and better polymer -filler interaction.

The Payne Effect Strain (Test conditions: Sweep test, Strain Angle 0.07 to 300.00%, Temperature:70°C, Frequency: 1Hz) is measured through Rubber Process Analyzer RPA 2000 premier from Alpha Technologies, USA in accordance with ASTM D 8059.

Table 3: Rubber compound and Properties

Table 4: Rubber Compound and its properties Better Processing Properties (Ref: Table 3 & 4):

NR:PBR diblend (70 phr: 30 phr) based motorcycle tyre tread base rubber composition reinforced by N220 carbon black is replaced with 5 to 20 phr of recovered carbon black (Fl to F4: Formulation related to invention) Mooney Viscosity ML (1+4) @ 125 °C is lowered by 5.6% to 17.9% when compared to NR:BR (70 phr:30 phr) blend reinforced by conventional N220 carbon black (Cl - Control) grade which infers better processing properties.

Similarly, NR:SBR:PBR triblend (70 phr: 15 phr: 15 phr) based motorcycle tyre tread base rubber composition reinforced by N330 carbon black is replaced with 2 to 20 phr of recovered carbon black (F5 to F8- Formulation related to invention) Mooney Viscosity ML (1+4) @ 125 °C is lowered by 3.48% to 11.04% when compared to NR:SBR:PBR triblend (70 phr: 15 phr: 15 phr) reinforced by conventional N330 carbon black (C2 - Control) grade which implies better processing properties.

NR:PBR diblend (70 phr: 30 phr) based motorcycle tyre tread base rubber composition reinforced by N220 carbon black is replaced with 5 to 20 phr of recovered carbon black (Fl to F4: Formulation related to invention) Mooney Scorch @ 125 °C, minimum viscosity (MV) value is lowered by 5.0% to 18.8% when compared to NR:PBR (70 phr:30 phr) blend reinforced by conventional N220 carbon black (Cl - Control) grade. Also, the Mooney Scorch time t5 value increased by 5.9% to 11.6% which implies process safety.

Similarly, NR:SBR:PBR triblend (70 phr: 15 phr: 15 phr) based motorcycle tyre tread base rubber composition reinforced by N330 carbon black is replaced with 2 to 20 phr of recovered carbon black (F5 to F8 - Formulation related to invention) Mooney Scorch @ 125 °C, minimum viscosity (MV) is lowered by 2.43 % to 11.65% when compared to NR:SBR:PBR triblend (70 phr: 15 phr: 15 phr) blend reinforced by conventional N330 carbon black (C2 - Control) grade. Also, the Mooney scorch time t5 value is increased by 1.4% to 5.6% which infers process safety.

Visco Elastic Properties:

NR:PBR blend (70 phr: 30 phr) based motorcycle tyre tread base rubber composition reinforced by N220 carbon black is replaced with 5 to 20 phr of recovered carbon black (Fl to F4: Formulation related to invention) provide rebound resilience % value improves from 5.9% to 11.6% when compared to NR:PBR (70 phr:30 phr) blend reinforced by conventional N220 carbon black (Cl - Control) grade which implies high rubber elasticity.

Also, NR:PBR blend (70 phr: 30 phr) based motorcycle tyre tread base rubber composition reinforced by N220 carbon black is replaced with 5 to 20 phr of recovered carbon black (Fl to F4: Formulation related to invention) provides tan delta @ 60 °C value is lowered by 3.9% to 17.4% when compared to NR:PBR (70 phr:30 phr) blend reinforced by conventional N220 carbon black (Cl - Control) grade which infers lower rolling resistance.

Moreover, the difference between storage modulus (G’0.7% - G ‘10%) in Fl to F4 formulation related to invention is lowered by 33.0 % to 74.4 % i.e., lower Payne effect when compared to NR:PBR (70 phr: 30 phr) blend reinforced by conventional N220 carbon black (Cl - Control).

Similarly, NR:SBR:PBR blend (70 phr: 15 phr: 15 phr) based motorcycle tyre tread base rubber composition reinforced by N330 carbon black is replaced with 5 to 20 phr of recovered carbon black (F5 to F8 - Formulation related to invention) provide rebound resilience % value improves from 3.8% to 12.5% when compared to NR:SBR:PBR blend (70 phr: 15 phr: 15 phr) reinforced by conventional N330 carbon black (C2- Control) grade which implies high rubber elasticity.

Also, NR:SBR:PBR triblend (70 phr: 15 phr: 15 phr) based motorcycle tyre tread base rubber composition reinforced by N330 carbon black is replaced with 5 to 20 phr of recovered carbon black (F5 to F8 - Formulation related to invention) provides tan delta @ 60 °C value is lowered by 7.3% to 14.6% when compared to NR:SBR:PBR triblend (70 phr: 15 phr: 15 phr) reinforced by conventional N330 carbon black (C2 - Control) grade.

Moreover, the difference between storage modulus (G’0.7% - G ‘10%) in F5 to F8 formulation related to invention is lowered by 12.50 % to 62.50 % i.e., lower Payne effect when compared to NR:SBR:PBR blend (70 phr: 15 phr: 15 phr) reinforced by conventional N330 carbon black (C2- Control) grade.

Overall, a motorcycle tyre tread base rubber composition with the diblend of NR and PBR produced using conventional reinforcing carbon black grade N220 replaced with 5 to 20 phr of recovered carbon black provides better processing properties, lower Payne effect, lower rolling resistance along with high rubber elasticity.

Similarly, a motorcycle tyre tread base rubber composition with the triblend of NR, SBR and PBR produced using conventional reinforcing carbon black grade N330 replaced with 5 to 20 phr of recovered carbon black provides better processing properties, lower Payne effect, lower rolling resistance along with high rubber elasticity.