Two-layered metal cord rubberized in situ by an unsaturated thermoplastic elastomer
A metal cord has an M+N construction with two concentric layers. An internal first layer or core includes M wire(s) of diameter d 1 , M having a value from 1 to 4. An external second layer includes N wires of diameter d 2 and is positioned around the core, the N wires being wound in a helix. Between the wires of the two layers are gaps, some or all of which include a filling rubber based on an unsaturated thermoplastic elastomer. The filling rubber may be, for example, based on an SBS or an SIS block copolymer. When used in a molten state, the thermoplastic elastomer presents no problem due to unwanted stickiness if the filling rubber overspills outside the cord after manufacture. The unsaturated and therefore (co)vulcanizable nature of the thermoplastic elastomer makes it compatible with diene rubber matrices used as calendering rubber in metal fabrics intended for reinforcing tires.
1. A metal cord that includes two concentric layers having an M+N construction, the cord comprising:
an internal first layer including M wire(s) of diameter d 1 , M having a value in a range from 1 to 4, the internal first layer being a core of the cord; and
an external second layer including N wires of diameter d 2 wound together in a helix, the external second layer being positioned around the core,
wherein, between the wires of the internal first layer and the external second layer are gaps, with at least some of the gaps containing a rubber or a rubber compound, and
wherein the rubber or the rubber compound includes an unsaturated thermoplastic elastomer.
2. The cord according to claim 1 , wherein the unsaturated thermoplastic elastomer is a styrene thermoplastic elastomer.
3. The cord according to claim 2 , wherein the unsaturated styrene thermoplastic elastomer includes polystyrene blocks and polydiene blocks.
4. The cord according to claim 3 , wherein the polydiene blocks are selected from a group of blocks consisting of: polyisoprene blocks, polybutadiene blocks, and mixtures thereof.
5. The cord according to claim 4 , wherein the unsaturated styrene thermoplastic elastomer is a copolymer selected from a group of block copolymers consisting of:
styrene/butadiene/styrene block copolymers, styrene/butadiene/butylene/styrene block copolymers, styrene/isoprene/stryrene block copolymers, styrene/butadiene/isoprene/styrene block copolymers, and mixtures thereof.
6. The cord according to claim 1 , wherein N has a value in a range from 5 to 15.
7. The cord according to claim 1 , wherein the external layer is a saturated layer.
8. The cord according to claim 1 , wherein the cord is incorporated as a strand of a multistrand rope.
9. A finished or semifinished rubber article or product, the article or product comprising a metal cord that includes two concentric layers having an M+N construction,
wherein the cord includes:
an internal first layer including M wire(s) of diameter d 1 , M having a value in a range from 1 to 4, the internal first layer being a core of the cord; and
an external second layer including N wires of diameter d 2 wound together in a helix, the external second layer being positioned around the core,
wherein, between the wires of the internal first layer and the external second layer are gaps, with at least some of the gaps containing a rubber or a rubber compound, and
wherein the rubber or the rubber compound includes an unsaturated thermoplastic elastomer.
10. The finished or semifinished rubber article or product according to claim 9 , further comprising a multistrand rope, wherein the metal cord is incorporated as a strand of the multistrand rope.
11. A tire comprising a metal cord that includes two concentric layers having an M+N construction,
wherein the cord includes:
an internal first layer including M wire(s) of diameter d 1 , M having a value in a range from 1 to 4, the internal first layer being a core of the cord; and
an external second layer including N wires of diameter d 2 wound together in a helix, the external second layer being positioned around the core,
wherein, between the wires of the internal first layer and the external second layer are gaps, with at least some of the gaps containing a rubber or a rubber compound, and
wherein the rubber or the rubber compound includes an unsaturated thermoplastic elastomer.
12. The tire according to claim 11 , further comprising a multistrand rope, wherein the metal cord is incorporated as a strand of the multistrand rope.