A method of selectively controlling the self-sealing ability of a tyre obtained by application of a sealing assembly on a drum and subsequent formation thereon of a precursor of a green tyre inclusive of liner and carcass, followed by shaping, curing and molding. The sealing assembly includes: a self-supporting thermoplastic film of polyamide or polyester and a layer of sealing material possessing viscoelasticity and stickiness features, which is associated with and supported by the self-supporting thermoplastic film. The sealing assembly is easily puncturable by a sharp-pointed element while it maintains such a deformability and stickiness that it helps in the transfer of the sealing material during ejection of the sharp-pointed element and limits the transferred material amount to such an extent that holes bigger than a predetermined value are not sealed.

A process for manufacturing a self-sealing elastomer composition, said process comprising the following steps: a masterbatch, comprising at least one diene elastomer and more than 30 phr of a hydrocarbon resin, is firstly manufactured by compounding these various components in a mixer at a temperature or up to a temperature called the hot compounding temperature which is above the softening point of the hydrocarbon resin; and then at least one crosslinking system is incorporated into the masterbatch thus prepared, by compounding everything in the same mixer or in a different mixer, at a temperature or up to a temperature which is kept below 100 C., in order to obtain said self-sealing composition.

Processes for producing a sealant layer-tire inner liner combination as well as a sealant layer-containing tire and related processes involving the sealant layer-containing tire are disclosed. The sealant layer is adhered to the tire inner liner, has a thickness of 2-8 mm and comprises 100 parts of at least one rubber, 300-500 phr of at least one tackifier, optionally one or more extenders, optionally at least one hydroscopic substance, and a cure package.

This invention reveals an uncured pneumatic tire which is comprised of a generally toroidal-shaped supporting carcass with an outer circumferential tread, two spaced beads, at least one ply extending from bead to bead, sidewalls extending radially from and connecting the tread to the beads, a sealant layer which is disposed inwardly from the supporting carcass, and an innerliner which is disposed inwardly from the sealant layer, wherein circumferential tread is adapted to be ground-contacting, and wherein the sealant layer is comprised of polyisobutylene or a butyl rubber, wherein the polyisobutylene or the butyl rubber has a number average molecular weight which is within the range of 30,000 to 100,000.