Abstract: An expandable bladder has at least one first layer of butyl material and one second layer of silicone material, radially external to the first layer. The first and second layers have an undulated interface profile defining mechanical-engagement elements between the first and second elastomer materials. A process for manufacturing bladder as well as a tire molding and vulcanizing apparatus incorporating the bladder.

Abstract: An expandable bladder has at least one first layer of butyl material and one second layer of silicone material, radially external to the first layer. The first and second layers have an undulated interface profile defining mechanical-engagement elements between the first and second elastomer materials. A process for manufacturing bladder as well as a tire molding and vulcanising apparatus incorporating the bladder.

Abstract: An expandable bladder for manufacturing pneumatic tyres is used in combination with a vulcanisation apparatus including, for example, a mould having a plurality of sidewall plates and tread sectors that, when the mould is closed, delimit a moulding cavity suitable for housing the green pneumatic tyre to be cured. The expandable bladder includes an elastomeric material obtained by curing an elastomeric composition which includes at least one butyl rubber and at least one compound having at least one double bond and an at least partially fluorinated alkyl or polyoxyalkylene chain.

Abstract: In a tyre for vehicle wheels, the tread band sidewalls and/or other structural elements of elastomer material have a layered structure which includes at least one first component and at least one second component of a material with different composition from that of the first component. The first and second components have an undulated interface profile, defining elements of mutual mechanical engagement. Also described is a process and an apparatus for manufacturing a tyre.

Abstract: An expandable bladder has at least one first layer of butyl material and one second layer of silicone material, radially external to the first layer. The first and second layers have an undulated interface profile defining mechanical-engagement elements between the first and second elastomer materials. A process for manufacturing bladder as well as a tyre moulding and vulcanising apparatus incorporating the bladder.

Abstract: An expandable bladder has at least one first layer of a natural or synthetic rubber-based material or a mixture thereof, and one second layer of silicone material, radially external to the first layer. The first and second layers have an undulated interface profile defining mechanical-engagement elements between the first and second elastomer materials. A process for manufacturing a bladder as well as a tyre manufacturing apparatus incorporating bladders is also disclosed.