Composite reinforcer sheathed with a layer of polymer that is self-adhesive to rubber
A composite reinforcer that can adhere directly to a diene rubber matrix is usable as a reinforcing element for a pneumatic tire. The composite reinforcer includes at least one reinforcing thread, such as a carbon steel cord. Covering each thread individually or several threads collectively is a layer of a thermoplastic polymer composition. The thermoplastic polymer composition includes at least one thermoplastic polymer have a glass transition temperature that is positive, a poly(p-phenylene ether) (PPE), and a functionalized unsaturated thermoplastic styrene (TPS) elastomer having a glass transition temperature that is negative. The TPS elastomer includes a functional group selected from: an epoxide group, a carboxyl group, an acid anhydride group, and an ester group. A process for manufacturing such a composite reinforcer is presented, as well as a process for producing a rubber article, especially a pneumatic tire, incorporating such a composite reinforcer.
1. A composite reinforcer comprising:
at least one reinforcing thread; and
a layer of a thermoplastic polymer composition covering each thread individually or plural threads collectively, of the at least one reinforcing thread, wherein the thermoplastic polymer composition includes:
a thermoplastic polymer having a glass transition temperature that is positive,
a poly(p-phenylene ether), and
a functionalized unsaturated thermoplastic styrene elastomer having a glass transition temperature that is negative,
wherein the thermoplastic polymer is selected from the group consisting of polyamides, polyesters, and polyimides, and
wherein the functionalized unsaturated thermoplastic styrene elastomer includes a functional group selected from the group consisting of an epoxide group, a carboxyl group, an acid anhydride group, and an ester group.
2. The composite reinforcer according to claim 1 , wherein the glass transition temperature of the thermoplastic polymer is above +20° C.
3. The composite reinforcer according to claim 1 , wherein the glass transition temperature of the functionalized unsaturated thermoplastic styrene elastomer is below −20° C.
4. The composite reinforcer according to claim 2 , wherein the glass transition temperature of the functionalized unsaturated thermoplastic styrene elastomer is below −20° C.
5. The composite reinforcer according to claim 1 , wherein a difference between the glass transition temperature of the thermoplastic polymer and the glass transition temperature of the functionalized unsaturated thermoplastic styrene elastomer is greater than 60° C.
6. The composite reinforcer according to claim 1 , wherein the thermoplastic polymer is an aliphatic polyamide or a polyester.
7. The composite reinforcer according to claim 1 , wherein the functionalized unsaturated thermoplastic styrene elastomer is a copolymer that includes styrene blocks and diene blocks.
8. The composite reinforcer according to claim 1 , wherein the poly(p-phenylene ether) has a glass transition temperature above 150° C.
9. The composite reinforcer according to claim 1 , wherein the poly(p-phenylene ether) is poly(2,6-dimethyl-1,4-phenylene ether).
10. The composite reinforcer according to claim 1 , wherein the functionalized unsaturated thermoplastic styrene elastomer includes between 5% and 50% styrene by weight.
11. The composite reinforcer according to claim 1 , wherein a minimum thickness of the layer is between 1 μm and 2 mm.
12. The composite reinforcer according to claim 1 , wherein the composite reinforcer is incorporated in a pneumatic tyre.
13. A method for manufacturing a composite reinforcer, comprising steps of:
providing at least one reinforcing thread;
providing a thermoplastic polymer composition that includes:
a thermoplastic polymer having a glass transition temperature that is positive,
a poly(p-phenylene ether), and
a functionalized unsaturated thermoplastic styrene elastomer having a glass transition temperature that is negative,
wherein the thermoplastic polymer is selected from the group consisting of polyamides, polyesters, and polyimides, and
wherein the functionalized unsaturated thermoplastic styrene elastomer includes a functional group selected from the group consisting of an epoxide group, a carboxyl group, an acid anhydride group, and an ester group; and
sheathing the at least one reinforcing thread with a layer of the thermoplastic polymer composition, wherein the sheathing covers each thread individually or plural threads collectively.