The present invention relates to compositions for elastomeric compounds for tyres, comprising monotetrazole compatibilizing agents characterised by precise activation temperatures, tyre components and tyres for vehicle wheels which comprise them. Advantageously, the present monotetrazole compatibilizing agents allow the breaking properties of the compounds to be improved while maintaining a high compatibilisation of the filler.

The present invention relates to elastomeric compositions for tyres and relative compounds, components and tyres comprising them, said compositions comprising an elastomeric polymer, a phenolic product, optionally already partially cross-linked, optionally an aldehyde and/or at least a methylene donor product and an oxidised carbon allotrope as a cross-linking catalyst. Advantageously, this catalyst is able to complete the cross-linking reactions of the phenolic resins in the conventional times and conditions of vulcanisation, or even more rapidly, providing mechanically stable compounds.

A tire comprises sidewalls (2), a crown region (3) provided with a tread (4), and a reinforcing structure (5) extending between the sidewalls (2) and passing via the crown region (3). At least one portion of the region of the tire that is axially inside the reinforcing structure (5) comprises an insert (6) comprising a first elastomer composition serving as a matrix, within which a second elastomer composition originating from recycled tires is distributed substantially uniformly, the proportion of said second elastomer composition being greater than or equal to 40%.

The present invention is directed to a pneumatic tire having a tread comprising a vulcanizable rubber composition comprising, based on 100 parts by weight of elastomer (phr), up to 100 phr of a solution polymerized styrene-butadiene rubber; from 5 to 50 phr of a fatty acid monoester of formula 1

##STR00001##

where R.sup.1 is selected from C1 to C8 linear or branched alkyl, C1 to C8 linear or branched alkenyl, and C2 to C6 linear or branched alkyl substituted with from one to five hydroxyl groups; R.sup.2 is C11 to C21 alkyl or C11 to C21 alkenyl; from 5 to 50 phr of a hydrocarbon resin having a Tg ranging from −40° C. to 20° C.; less than 10 phr of a petroleum-derived oil; and from 50 to 130 phr of silica. optionally, from about 1 to 50 phr carbon black.

A rubber composition is based on an elastomeric matrix comprising at least 50 phr of butadiene elastomer, at most 60 phr of filler comprising from 5 to 30 phr of carbon black which predominantly comprises a carbon black termed black G, and from 2 to 30 phr of inorganic filler. A finished or semi-finished rubber item and a tire are made from this composition.

The present invention regards a solid master elastomeric composition (masterbatch, MB) comprising silicate fibres with needle-shaped morphology of nanometric size, characterised by high fibre content and uniformity, a process advantageous for the preparation thereof and its use in manufacturing tyres for vehicles. Advantageously the present elastomeric composition allows minimising the drawbacks associated with the handling of the powdery fibres in the manufacturing of compounds for tyres, without altering the final performances thereof.

A rubber compound for a pneumatic tyre portion comprising a cross-linkable unsaturated chain polymeric base, silica, processing oil and vulcanization agents; said reinforcing filler comprising silica. The ratio in phr between the reinforcing filler and the processing oil is greater than or equal to 3.

A sulfur-crosslinked rubber mixture, in particular for vehicle tires, and a vehicle tire. The sulfur-crosslinked rubber mixture contains at least the following constituents: at least one diene rubber and 0.5 to 10.0 phr of at least one anti-reversion agent and 2.0 phr or more of at least one para-phenylenediamine and 2.0 phr or more of at least one dihydroquinoline
and wherein the network node spacing of the crosslinked rubber mixture is 4.5 to 10 nm.

The present invention relates to a tyre for vehicle wheels comprising at least one structural element comprising a crosslinked elastomeric material obtained by crosslinking a crosslinkable elastomeric composition comprising a predispersion of natural rubber and lignin obtained by co-precipitation from latex, where said lignin has a concentration of phenolic groups higher than 2 mmol per gram of lignin, and where said predispersion comprises an amount of said lignin such as to provide, in said crosslinkable elastomeric composition, a concentration of lignin equal to or lower than about 25 phr.

The present invention relates to new vulcanisable elastomeric compositions for components of tyres, comprising modified silicate fibres as fillers. The silicate fibres are modified according to the process with controlled pH of the invention. In addition, the invention regards components of tyres, comprising elastomeric materials obtainable by vulcanisation of said compositions, and tyres for vehicles comprising one or more of said components. The vulcanised elastomeric materials according to the invention are characterised by good static and dynamic mechanical properties, in particular by particularly low hysteresis. Advantageously the tyres of the invention comprising one or more of said components have a limited rolling resistance.