Process for making tires for vehicle wheels

A process for producing tires for vehicles wheels comprises the following steps: (a) obtaining at least one crosslinkable elastomeric material; (b) making a raw tire by assembling a plurality of structural elements, at least one of which comprising the at least one crosslinkable elastomeric material; (c) molding and crosslinking the raw tire so as to obtain a finished tire. The step of obtaining the at least one crosslinkable elastomeric material includes: (i) mixing at least one layered clay, at least one further filler and at least one elastomer, so as to at least partially delaminate the at least one layered clay within the at least one elastomer; (ii) adding to the mixt. prepd. in step (i) at least one quaternary alkyl onium cation selected from quaternary alkyl ammonium or quaternary alkyl phosphonium or mixt. thereof. Thus, a crosslinkable elastomeric material with superior properties was prepd. by mixing in a first phase, isoprene rubber (100 phr), carbon black (50 phr), Dellite HPS nanosized layered clay (4.8 phr) and Arquad HC (3.5 phr) in a Banbury mixer, followed by admixing Silane NXT (0.8 phr) and phthalic anhydride (1.0 phr), after which the masterbatch was discharged at approx. 145. In Phase 2, the masterbatch, stearic acid (2.0 phr), zinc oxide (4.0 phr) and 6PPD (2.0 phr) were introduced into the mixer at approx. 700, mixed for about 3.5 min and finally discharged at approx. 125. Productive mixing was performed on a two roll mill by adding sulfur, DCBS and PVI to the masterbatch, at 50-70 for about 5 min.