Abstract:
A sulphur-vulcanizable rubber composition usable for the manufacture of tires, based on at least: (A)—one diene elastomer selected from the group consisting of polybutadienes, natural rubber, synthetic polyisoprenes, butadiene copolymers, isoprene copolymers and mixtures of these elastomers (component A); (B)—a reinforcing white filler (component B); (C)—a coupling agent (white filler/diene elastomer) bearing at least one activated double ethylene bond (component C), with which there is associated: (D)—between 0.05 and 1 phr (parts by weight per hundred of elastomer) of a heat-triggered radical initiator (component D). The coupling agent is in particular an alkoxysilane of the family of alkoxy(C1–C4)-silylpropyls, in particular a trialkoxy(C1–C4)-silylpropyl methacrylate, in particular trimethoxy-silylpropyl methacrylate. Process for preparing such a rubber composition. Tire or semi-finished product, in particular tread, for a tire comprising a rubber composition according to the invention.
Abstract:
The invention concerns a rubber sulfur-vulcanizable composition designed for manufacturing tire treads, comprising at least a diene elastomer, a white filler as reinforcing filler and as coupling agent (white filler/elastomer) a multifunctionalized polyorganosiloxane comprising per molecule: a) at least a first siloxyl unit bearing, on the silicon atom, at least one linear or branched C1-C15 alkoxyl radical; and b) at least a second siloxyl unit bearing, on the silicon atom, at least one radical of general formula Z—SH, Z being a linear or branched divalent hydracarbon, comprising preferebly 2 to 30 carbons.
Abstract:
Tire (10) comprising a tread (40) having a mean radial height HB, an outer edge (45) and an inner edge (46), the axial distance between the outer edge (45) and the inner edge (46) defining the axial width L of the tread, the tread comprising a first portion (411) made of a first rubber compound, extending from the outer edge (45) to a first axial position at an axial distance from the outer edge of between 20% and 40% of the axial width; a second portion (412) made of a second rubber compound, extending from said first axial position to a second axial position at an axial distance from the outer edge of between 50% and 60% of the axial width L; a third portion (413) made of a third rubber compound extending from said second axial position to a third axial position at an axial distance from the outer edge of between 80% and 90% of the axial width L; and a fourth portion (414) made of a fourth rubber compound, extending from said third axial position to the inner edge (46) of the tread, wherein said first and third rubber compounds are predominantly filled with carbon black filler, wherein said second and fourth rubber compounds are predominantly filled with non carbon black filler, and wherein said first rubber compound and said third rubber compound have a value for tan δ at 0° C., at a stress of 0.7 MPa, that is lower than that of said second rubber compound and said fourth rubber compound.
Abstract:
Tire (10) comprising a tread (40) having a mean radial height HB, an outer edge (45) and an inner edge (46), the axial distance between the outer edge (45) and the inner edge (46) defining the axial width L of the tread, the tread comprising a first portion (411) made of a first rubber compound, extending from the outer edge (45) to a first axial position at an axial distance from the outer edge of between 20% and 40% of the axial width; a second portion (412) made of a second rubber compound, extending from said first axial position to a second axial position at an axial distance from the outer edge of between 50% and 60% of the axial width L; a third portion (413) made of a third rubber compound extending from said second axial position to a third axial position at an axial distance from the outer edge of between 80% and 90% of the axial width L; and a fourth portion (414) made of a fourth rubber compound, extending from said third axial position to the inner edge (46) of the tread, wherein said first and third rubber compounds are predominantly filled with carbon black filler, wherein said second and fourth rubber compounds are predominantly filled with non carbon black filler, and wherein said first rubber compound and said third rubber compound have a value for tan δ at 0° C., at a stress of 0.7 MPa, that is lower than that of said second rubber compound and said fourth rubber compound.
Abstract:
A rubber composition which is free of precursor of at least one carcinogenic nitrosamine, is capable of vulcanization at a temperature of between 95° C. and 140° C., and has a vulcanization system which includes: a) sulfur; b) an accelerator compound; c) an ultra-accelerator compound; d) a vulcanization amine activator. A process for vulcanizing this composition in the manufacture of a new tire or in the repair and/or recapping of a worn tire.