Hybrid cords for tire reinforcement

• US 8,079,208 B2
• Filed: 12/04/2008
• Issued: 12/20/2011
• Est. Priority Date: 12/04/2007
• Status: Active Grant

• Current Assignee: DuPont Safety & Construction, Inc. (DuPont de Nemours, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Volpi, Alessandro
• Primary Examiner(s): Hurley, Shaun R
• Application Number:
  US12/327,952
• Publication Number:
  US 20090159171A1
• Time in Patent Office: 1,111 Days
• Field of Search: 572/12, 572/13, 572/14, 572/16, 572/17, 572/18, 572/20, 572/21, 572/22, 572/23
• US Class Current: 57/222
• CPC Class Codes: B60C 9/0042 Reinforcements made of synthetic materials
• CPC Class Codes: B60C 9/005 Reinforcements made of different materials, e.g. hybrid or composite cords
• CPC Class Codes: D02G 3/48 Tyre cords tyre reinforcements B60C9/00; metal cords for reinforcing rubber or plastic articles D07B1/0606
• CPC Class Codes: D07B 1/062 the reinforcing cords being characterised by the strand configuration
• CPC Class Codes: D10B 2331/021 aromatic polyamides, e.g. aramides
• CPC Class Codes: Y10T 152/10 Tires, resilient

Abstract

A cord for reinforcing tires having a core of at least one p-aramid filament that has a modulus greater than about 6.5 N/dTex and a sheath of steel strands that are helically wound around the p-aramid filament. The steel strands consist of either a single steel wire or multiple steel wires twisted together.

Claims

1. A hybrid cord for reinforcing tires, the cord comprising:

a core of at least one p-aramid filament and

a sheath of steel strands helically wound around the p-aramid filament;

wherein the p-aramid filament has a modulus greater than about 6.5 N/dTex.

2. The hybrid cord of claim 1, wherein the steel strands each consist of a single steel wire.

3. The hybrid cord of claim 1, wherein the steel strands each consist of cables made by twisting together multiple steel wires.

4. The hybrid cord of claim 1, wherein greater than 90% of the outside surface of the core is covered by the sheath.

5. The hybrid cord of claim 1, wherein the helical angle is between about 8 and 21°

.

6. The hybrid cord of claim 1, wherein the sheath is made of fine steel wire having a diameter of between about 0.04 mm and 0.125 mm.

7. A support structure for a tire, comprising one or more hybrid cords according to claim 1 and a supporting matrix.

8. The support structure of claim 7, which is a belt.

9. The support structure of claim 7, which is a carcass.

10. The support structure of claim 7, which is a bead reinforcement chafer.

11. A tire comprising one or more hybrid cords according to claim 1.

13. A method for manufacturing a support structure for a tire, comprising the step of embedding the hybrid cord of claim 1 in a support matrix.

14. A method for manufacturing a tire, comprising the step of incorporating a support structure according to claim 7 into a tire.

12. A method for manufacturing a hybrid cord comprising the steps:

providing a core of at least one p-aramid filament having a modulus greater than about 6.5 N/dTex and

wrapping the core with a plurality of steel strands, so as to form a sheath of steel strands.