Pirelli Pneumatici S.p.a.

Pirelli Coordinamento Pneumatici S.p.a.

Pirelli Tyre S.p.a.

Roberto Pessina

Renato Caretta

Luciano Garro

Angela Amaddeo

Antonio Proni

Mike Patterson

Alan Bottomley

Andrew Gooding

A process for producing a rubber compound for tires, where the ingredients of the rubber compound include: a polymer base containing an unsaturated chain which can be crosslinked with sulphur-based systems; at least one silica-based reinforcing filler; a silica-binding agent including a silane containing at least one sulphur atom; and a vulcanizing system. The process includes the steps of feeding the polymer base, the silica-based reinforcing filler, and the silica-binding agent ingredients continuously into a path for mixing and advancing an ingredient blend, wherein the mixing and advancing of the blend take place together. The path includes an initial stretch, an intermediate stretch, and a final stretch; each stretch defined between respective inlet and outlet sections. The process also includes controlling a heat profile of the blend in the initial stretch to maintain temperature and viscosity values for the blend in the outlet section of the initial stretch within defined ranges, and feeding the vulcanizing system continuously into the inlet section of the final stretch.

Continuous process for producing semi-finished rubber products with a silica reinforcing filler, for tyres, and tyres thus produced

A process for producing a vulcanizable rubber composition containing silica and carbon black, comprises the step of intimately mixing at a temperature of from 130&deg; to 180&deg; C. at least a first cross-linkable unsaturated chain polymer with a first carbon black-based reinforcing filler, so as to obtain a first rubber composition capable of allowing a subsequent effective dispersion of a second silica-based reinforcing filler and of a second cross-linkable unsaturated chain polymer. The rubber composition thus obtained shows a homogeneous dispersion of the reinforcing fillers, in particular of the silica-based reinforcing filler, constant physical-mechanical characteristics, and improved drawability, and is particularly suitable for the manufacture of tire treads with low rolling resistance.

Process for producing a vulcanizable rubber composition including carbon black-based and silica-based reinforcing fillers

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Paderno Dugnano, Italy

Roberto Pessina