摘要:
A crosslinkable elastomeric composition includes at least one diene elastomeric polymer and at least one organic quaternary ammonium salt. The at least one diene elastomeric polymer may have a glass transition temperature (Tg) below 20° C. The at least one organic quaternary ammonium salt may be present in an amount from 0.1 phr to 10 phr. The elastomeric composition may include at least one primary accelerator selected from thiazoles, sulphenamides, and/or xanthogenates. The elastomeric composition may be substantially free of additional secondary accelerators. The elastomeric composition may include at least one reinforcing filler, such as carbon black and/or silica. A tyre for a vehicle wheel includes at least one structural element including the elastomeric composition. The tyre may include a carcass structure, a belt structure, a tread band, and a pair of sidewalls. The at least one structural element including the elastomeric composition may be the tread band.
摘要:
A process for continuously producing an elastomeric composition includes providing at least one extruder, metering and feeding at least one elastomer, at least one filler, and ingredients different from elastomers and fillers into the at least one extruder, mixing and dispersing the at least one filler and the ingredients different from elastomers and fillers into the at least one elastomer using the at least one extruder, and extruding a resulting elastomeric composition. The at least one extruder includes the housing and at least one screw rotatably mounted in the housing. The housing includes at least one feed opening and a discharge opening. At least one of the ingredients different from elastomers and fillers includes a subdivided product including one or more minor ingredients dispersed in at least one thermoplastic binding agent. An apparatus for continuously producing the elastomeric composition is also disclosed.
摘要:
Elastomeric ethylene/propylene or ethylene/propylene/polyene copolymers containing small amounts of one or more &agr;-olefins are prepared by a slurry process wherein the polymerization reaction is carried out in a mixture of liquid propylene and alpha-olefin.
摘要:
A process for continuously producing an elastomeric composition includes metering and feeding at least one elastomer and at least one filler into at least one extruder, mixing and dispersing the at least one filler into the at least one elastomer using the at least one extruder, and passing the composition that results through at least one static mixer. An apparatus for continuously producing the composition includes at least one twin-screw extruder, at least one metering device, and at least one static mixer. The at least one extruder includes a housing and two screws rotatably mounted in the housing. The housing includes at least one feed opening and a discharge opening. The at least one metering device meters and feeds at least one elastomer and at least one filler into the at least one extruder. The composition discharged from the discharge opening passes through the at least one static mixer.
摘要:
A process for continuously producing an elastomeric composition includes metering at least one elastomer, at least one filler, and at least one minor ingredient; feeding the at least one elastomer, the at least one filler, and the at least one minor ingredient into at least one extruder; mixing and dispersing the at least one filler and the at least one minor ingredient into the at least one elastomer using the at least one extruder; obtaining a subdivided product from a resulting elastomeric composition discharged from the at least one extruder; accumulating an amount of the subdivided product; and stirring the accumulated amount of the subdivided product. An apparatus for continuously producing an elastomeric composition includes at least one extruder, at least one first metering device, at least one second metering device, at least one device for obtaining a subdivided product, and at least one accumulating and stirring device.
摘要:
A method for reducing elongational viscosity of an elastomeric composition includes adding at least one elongational-viscosity-reducing additive to the elastomeric composition in an amount so that the elongational viscosity of the elastomeric composition, measured at 120° C. and at a shear rate of at least 1000 sec−1, is at least 10% less than the elongational viscosity, measured at 120° C. and at the shear rate of at least 1000 sec−1, of the elastomeric composition without the at least one additive. A process for producing a tyre includes feeding an elastomeric composition to an extruder; forming, by extrusion, the elastomeric composition as a continuous elongated element; and depositing the elongated element on a support in a plurality of coils to make up a structural element of the tyre. Forming the elastomeric composition is carried out at the shear rate. The elastomeric composition comprises the at least one additive.
摘要:
A tyre for a two-wheeled vehicle includes a carcass structure, a belt structure, a tread band, and a pair of sidewalls. The carcass structure includes at least one carcass ply. Opposite lateral edges of the carcass structure are associated with respective bead wires. The belt structure is associated with at least one layer of a crosslinked elastomeric material. The elastomeric material includes at least one diene elastomeric polymer and at least one layered inorganic material comprising an individual layer thickness from 0.01 nm to 30 nm. A process for producing the tyre includes manufacturing the tyre by assembling the at least one carcass ply, the belt structure, and a tread; associating the at least one layer of a crosslinkable elastomeric material with the belt structure; subjecting the tyre to moulding in a cavity formed in a vulcanization mould; and subjecting the tyre to crosslinking by heating.
摘要:
Catalysts for the polymerization of olefins comprise the product of the reaction between: (A) a titanium, zirconium or hafnium product with substituted cyclopentadiene ligands, (B) a mixture of two organometallic aluminium compounds, with at least one of the groups bound to the aluminium being other than a linear alkyl, and (C) water. When used in the polymerization of olefins, these catalysts show higher activities, at short residence times, than corresponding catalysts obtained from the individual components of the above-mentioned mixtures of aluminium compounds.
摘要:
A process for the preparation of amorphous copolymers of ethylene with &agr;-olefins and optionally minor amounts of polyenes are disclosed, which have the following characteristics: (A) the % by mole content of &agr;-olefin in the copolymer (%&agr;) and the ratio between the molar amount of &agr;-olefin diads and the molar content of &agr;-olefin in the copolymer (&agr;&agr;/&agr;) satisfy the following relationship: (%&agr;)−250 (&agr;&agr;/&agr;)≧10 (B) less than 2% of the CH2 groups in the polymeric chain are in sequences (CH2)n, wherein n is an even number. These copolymers are obtained by operating in the presence of particular metallocene-based catalysts having two fluorenyl groups joined together through a bridging group.
摘要:
Catalysts for the polymerization of olefins comprise the product of the reaction between: (A) a titanium, zirconium or hafnium product with substituted cyclopentadiene ligands, (B) a mixture of two organometallic aluminium compounds, with at least one of the groups bound to the aluminium being other than a linear alkyl, and (C) water. When used in the polymerization of olefins, these catalysts show higher activities, at short residence times, than corresponding catalysts obtained from the individual components of the above-mentioned mixtures of aluminium compounds.