Self-sealing tyre for vehicle wheels
AssigneePirelli Tyre S.p.A.
InventorsLuca Giannini, Cristiano Puppi, Marco Nahmias Nanni, Michela Caprio
Life of this patent
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Abstract
A self-sealing tire for vehicle wheels includes: a carcass structure, a tread band applied in a radially external position to the carcass structure at least in a crown area of the tire, a liner applied in a radially inner position to the carcass structure, and a layer of sealing material applied in a radially inner position to the carcass structure and which extends axially at least in all the crown area of the tire in which the sealing material includes a partially chemically crosslinked composition including an unsaturated styrene thermoplastic elastomer.
Claims27
A self-sealing tyre for vehicle wheels obtained by vulcanizing a green self-sealing tyre comprising:
- a carcass structure, a tread band applied in a radially external position to said carcass structure at least in a crown area of the tyre, a liner applied in a radially inner position to said carcass structure, and a layer of sealing material applied in a radially inner position to said carcass structure and which extends axially at least in all the crown area of the tyre, said layer of sealing material comprising at least a layer of sealing material comprising a sealing composition comprising:
- (a) at least 20 phr of at least an unsaturated styrene thermoplastic elastomer;
- (b) from 0 phr to 80 phr of at least a diene elastomer;
- (c) from 4 phr to 6 phr of a crosslinking agent, the amount of the crosslinking agent in the sealing composition being such that:
- V×S′(10 Hz)=A
- wherein:
- V is an amount of the crosslinking agent expressed in meqv/100 g of composition;
- S′ is a value of a moment of torsion strength in phase with deformation of the sealing material detected before crosslinking, expressed in dNm, measured with an oscillating rheometer at 50° C., at 25% of dynamic deformation and at 10 Hz;
- and
- A is a parameter with value higher than 1.4;
- and
- (d) from 100 to 200 phr of an extension oil.
A process for the preparation of a self-sealing tyre for vehicle wheels comprising:
- preparing a layer of sealing material;
- wherein the preparation of the layer of sealing material comprises:
- feeding in a mixer comprising a housing, at least a screw revolving assembled in said housing comprising at least a feed opening and a discharge opening, said sealing composition comprising:
- (a) at least 20 phr of at least an unsaturated styrene thermoplastic elastomer;
- (b) from 0 phr to 80 phr of at least a diene elastomer;
- (c) from 4 phr to 6 phr of a crosslinking agent,
- wherein the amount of the crosslinking agent in the sealing composition is such that:
- V×S′(10 Hz)=A
- wherein:
- V is an amount of the crosslinking agent expressed in meqv/100 g of composition;
- S′ is a value of a moment of torsion strength in phase with deformation of the sealing material detected before crosslinking, expressed in dNm, measured with an oscillating rheometer at 50° C., at 25% of dynamic deformation and at 10 Hz;
- and
- A is a parameter with value higher than 1.4;
- and
- (d) from 100 to 200 phr of an extension oil;
- mixing said sealant composition;
- and
- discharging said sealant composition from the mixer using the discharge opening;
- forming a green tyre comprising a carcass structure, a tread band applied in a radially external position to said carcass structure at least in a crown area of the tyre, a liner applied in a radially inner position to said carcass structure, and said layer of sealing material applied in a radially inner position of said carcass structure and which extends axially at least in all the crown area of the tyre;
- and
- conforming, molding and vulcanizing said green tyre.
Dependencies are inferred from the claim text.