Cryogenic Grinding in Tire Recycling

Rubber composition for tires with improved wear resistance, breaking strength, and processability. The composition contains a rubber component and carbon black with specific properties. The carbon black has an oil absorption number of 105-122 mL/100g, CTAB specific surface area of 130-153 m2/g, D50/Dst ratio of 0.75-0.88, oil absorption difference of 11-33 mL/100g, and hydrogen evolution of 2300-3500 ppm. This carbon black provides wear resistance and breaking strength while avoiding excessive structure and agglomeration for better processability compared to conventional carbon blacks.

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Benzoxazine-functionalized diene-based elastomers with reinforcing properties for rubber compositions like tires. The elastomers have polymer chains with repeat units from conjugated dienes like butadiene, isoprene, and styrene, and benzoxazine rings attached via spacers. The spacers are 3-8 carbon atoms long. The benzoxazine groups provide reinforcement when attached to the polymer chains. The elastomers can be used in rubber compositions for tire reinforcement instead of carbon black or silica.

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Metallic reinforcing cord for tires with improved adhesion and reduced corrosion compared to traditional metallic cords. The cord has a helical structure with a specific spacing between the metallic wires. The spacing allows the tire rubber to penetrate between the wires for better adhesion. The cord provides a balance of elongation and rigidity like textile cords at low loads, but higher rigidity like metallic cords at high loads. This is achieved by twisting the metallic wires together with a specific pitch.

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Reinforcing material and structure with improved reinforcement performance. The reinforcing material has a resin layer with specific components to enhance adhesion and strength. The resin layer contains a thermosetting resin, diene rubber, tackifier resin, and vulcanizing agent. The tackifier resin has a softening temperature of 75°C to 100°C and a bromine value of 30 g/100g or more. This tackifier composition provides good tack for initial adhesion while also allowing the resin to cure and harden for long-term strength. The reinforcing structure uses this reinforcing material to reinforce an object by applying the reinforcing material as a layer on the object.

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A method to make uniformly cured high-modulus graphene oxide/natural rubber tires that have improved wear resistance and tear strength. The method involves optimizing the vulcanization process for thick rubber tires using specific ingredient ratios. It balances internal and external rubber cure to prevent over or under vulcanization. The ratios are: 0.5-5% graphene oxide, 40-120% carbon black, 1-20% activator, 1-20% softener, 1-10% anti-aging agent, 1-10% antioxidant, 1-20% vulcanization accelerator, 1-20% vulcanizing agent, and 1-20% interface modifying agent.

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A method to improve the properties of graphene-modified natural rubber composites by enhancing interfacial interaction between the rubber matrix and graphene. The method involves loading a free radical scavenger onto the surface of reduced graphene oxide (rGO) during its preparation. When the rGO-modified rubber is mixed, the scavenger annihilates free radicals generated from the rubber due to heat or force, improving interfacial interaction beyond hydrogen bonding. This increases rubber bound to rGO, enhances crosslink density, and improves strength and toughness of the graphene-modified rubber composite.

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Chemically modified precipitated silica with improved compatibility with polymeric matrices. The silica is modified during the precipitation process by adding alkali metal alkyl siliconates. This allows the formation of silica chemically modified with alkyl groups. The modification takes place during the precipitation without additional steps. The modified silica can be used as a reinforcing filler in polymeric compositions like tires.

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The escalating environmental challenges posed by waste rubber tyres (WRTs) necessitate innovative solutions to address their detrimental effects on the geoenvironment. Thus, knowledge about recent advancements in material recovery from WRTs, emphasising utilisation within framework of United Nations Sustainable Development Goals (SDGs) and circular economy principles, is need hour. Keeping this mind, various techniques generally used for recovery, viz., ambient, cryogenic, waterjet, so on, which unveil approaches reclaiming valuable resources (viz., recycled rubber, textiles, steel wires, etc.) WRTs devulcanisation physical, chemical, microbial) are elaborated paper. In parallel, paper explores recovered materials, highlighting application geotechnical geoenvironmental engineering development projects while addressing necessary precautions associated risks/concerns. This incorporates principles into focuses achieving SDGs promoting resource efficiency minimising impact.

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Method to prepare a wet master batch elastomer composition for making rubber with excellent processability and abrasion resistance. The method involves dispersing silica particles and an organic silane coupling agent in a styrene-butadiene rubber (SSBR) solution, stirring to pulverize the silica while modifying its surface with the coupling agent, removing solvent, drying, and solidifying to create a composite. Compounding this composite with additional additives makes a wet master batch elastomer composition with improved silica dispersion and binding strength in the final rubber. The composite has 8-20 parts organic silane coupling agent per 100 parts SSBR.

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Rubber composition for tires with enhanced wet grip performance, strength, and tensile properties. The composition contains a diene rubber, silica, and a silane-modified resin with a modulus of 700-1200 MPa and melting temperature of 110-140°C. The silane-modified resin improves silica dispersion and rubber matrix interaction compared to conventional silanes.

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Process to make composite materials for elastomeric products like tires with improved sustainability and adhesion. The process involves activating textile reinforcement yarns with a bath containing polyisocyanates, waxes, and surfactants before immersing them in the rubber mixture. This coating improves adhesion between the yarns and surrounding rubber. The coated yarns are then used to create the composite material. The activation bath can be made from recycled materials like post-consumer PET bottles. The composite with recycled yarns provides similar performance to conventional composites but with lower environmental impact. The vulcanized composite material and resulting elastomeric products, like tires, have improved sustainability and adhesion compared to conventional composites.

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Rubber composition for pneumatic tires that improves durability without sacrificing elongation. The composition contains a diene-based rubber, modified diene-based rubber, carbon black, and phosphoric acid-modified cellulose nanofiber. The modified diene-based rubber improves rubber strength, while the nanofiber further enhances strength. The composition allows reducing filler like silica to improve elongation. The composition can be used in vulcanized rubber parts of tires.

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Silica-filled natural rubber compositions for tire treads that provide improved properties like tensile strength, tear resistance, wear resistance, and impact resistance compared to traditional natural rubber treads. The compositions contain natural rubber, functionalized synthetic polyisoprene, and a silica filler. The functionalized synthetic polyisoprene has silica-interactive functional groups that impart polymer-filler interaction to the natural rubber domains in the composition, resulting in enhanced properties from both the natural rubber and the functionalized synthetic polyisoprene.

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Polysaccharide-elastomer masterbatch for making reinforced rubber compositions with reduced water content. The masterbatch is made by mixing a polysaccharide dispersion with an elastomer latex and then coagulating and drying the mixture. This avoids adding water during masterbatch production, allowing lower water content in the final rubber compound. The polysaccharide provides reinforcement and reduces rolling resistance compared to carbon black. The masterbatch can be used in applications like tires, belts, footwear, coatings, etc.

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A pollution-free method for recycling tires that involves cryogenic freezing, crushing, and sieving instead of shredding and high-temperature treatment. The method involves shredding tires, spraying them with water, filtering, drying, freezing, crushing, separating metal fibers, crushing again, sieving, and screening to produce clean tire particles. The cryogenic freezing step reduces odor, dust, and pollution compared to high-temperature processing.

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Pollution-free tire recycling method using cryogenic freezing to recycle tires without generating high pollution levels. The process involves shredding tires, spraying them with water, blow-drying, freezing to -150 to -300°C, crushing, separating metal fibers, further crushing, cyclone separating, and screening to produce fine tire particles. This cryogenic recycling reduces odor, dust, and pollution compared to high-heat recycling.

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A waste tire recycling system that pulverizes tires into rubber powder without pollution. The system involves a series of crushing, washing, freezing, and grinding steps. The tire is first crushed into fragments. The fragments are washed and then crushed again to make smaller fragments. These fragments are then frozen and ground into primary powder. The primary powder is split and further frozen and ground into secondary powder. This multi-stage freezing and grinding process allows efficient pulverization of tires into rubber powder without generating pollutants like dioxins.

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A cold energy recovery system for recycling waste tires and plastics into powder using liquid nitrogen. The system has a material tank with chambers, a feeding pipe, a liquid nitrogen chamber, a powder tank, and pipes connecting them. Nitrogen from the liquid nitrogen chamber is pumped into the feeding pipe to cool the material. The cooled material goes to the liquid nitrogen chamber for further cooling. Nitrogen from there is pumped into the feeding pipe to cool more material. The powder produced in the liquid nitrogen chamber is pumped to the powder tank. This recycles and reuses the nitrogen's cold energy to reduce waste. The chambers, pipes, and tanks are insulated to further minimize cold energy loss.

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A device for crushing old tires using refrigerated airflow that freezes and crushes tires in a uniform and efficient manner. The device has a crushing chamber, pre-cooling chamber, and heat exchange chamber. The crushing chamber has a rotating shaft with connecting rods and a top plate for tire crushing. The pre-cooling chamber has a refrigerator and the heat exchange chamber has an exhaust pipe. Air compressor cools and pressurizes air, which is sprayed downward by the first branch pipe and upward by the second branch pipe to freeze the tires. The reversing airflow and high pressure crush the frozen tires. The uniform freezing prevents uneven crushing. The heat exchange recovers refrigerant energy.

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A method to produce high-quality rubber powder from waste tires for use in tire treads. The method involves cryogenic grinding of the tire rubber at sub-glass transition temperatures to achieve small particle sizes. It uses a two-stage nitrogen cooling process with normal and low temperatures. This produces a high proportion of fine rubber powder with improved properties for tire treads compared to conventional grinding. The cryogenic grinding prevents heat buildup and stickiness, allowing finer sizes. The resulting powder can be used in tire treads for better performance and sustainability.

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