Tread comprising tread pattern elements covered with an impregnated fibre assembly

Patent metadata

Field	Value
Publication number	US-9962996-B2
Application number	US-201214365820-A
Country	US
Kind code	B2
Filing date	Dec 14, 2012
Priority date	Dec 16, 2011
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A tread for a pneumatic tire includes tread pattern elements and cuts. Each tread pattern element includes lateral faces and a contact face that comes into contact with a road surface when the tire is being driven thereon. A boundary between the contact face and the lateral faces forms at least one edge corner. The cuts are formed as grooves and/or sipes, with the cuts being delimited by opposing lateral faces of the tread pattern elements. Each tread pattern element is formed of at least one rubber compound. When the tread is viewed in cross section in a plane normal to an axis of rotation of the tire and passing through a contact face of a tread pattern element, at least one of the cuts adjacent to that contact face is covered at least in part with a covering layer that contains a woven or nonwoven fiber assembly.

First claim

The invention claimed is:

1. A tread for a pneumatic tyre, the tread comprising:
a plurality of tread pattern elements, each tread pattern element including lateral faces and a contact face that is intended to come into contact with a road surface when the tyre is being driven thereon, a boundary between the contact face and the lateral faces forming at least one edge corner; and
a plurality of cuts forming grooves and sipes, the cuts being delimited by opposing lateral faces of the tread pattern elements,
wherein each tread pattern element is formed of at least one base compound, the base compound being a first rubber compound,
wherein the tread includes first and second tread pattern elements separated by a groove, the first tread pattern element including a first contact face, a first lateral face, and a first sipe, the second tread pattern element including a second contact face, a second lateral face, and a second sipe,
wherein the first lateral face and the second lateral face oppose each other to delimit the groove therebetween,
wherein, when a cross section of the tread is viewed in a plane normal to an axis of rotation of the tyre and passing through the first and second contact faces and the first and second lateral faces, the groove is covered at least in part with a covering layer containing a woven or nonwoven fibre assembly, the covering layer being formed of a material different from the base compound,
wherein, when the tread is viewed in the cross section, the groove is disposed between the first sipe and the second sipe, and
wherein the base compound is exposed on an entirety of each of the first contact face, the second contact face, opposing lateral faces that delimit the first sipe, and opposing lateral faces that delimit the second sipe.

2. The tread according to claim 1 , wherein
the covering layer includes an elastomeric material, and
the fibre assembly is impregnated with the elastomeric material.

3. The tread according to claim 2 , wherein an apparent density of the fibre assembly prior to impregnation with an elastomeric material is less than 0.4, with less than 0.25 being preferable for the apparent density of the fibre assembly.

4. The tread according to claim 2 , wherein the elastomeric material includes a composition based on at least one diene elastomer.

5. The tread according to claim 4 , wherein the at least one diene elastomer is selected from a group of elastomers consisting of: polybutadienes, natural rubber, synthetic polyisoprenes, butadiene copolymers, isoprene copolymers, and blends thereof.

6. The tread according to claim 4 , wherein the composition includes sulphur.

7. The tread according to claim 6 , wherein a sulphur content of the composition is higher than 20 parts per hundred parts rubber.

8. The tread according to claim 2 , wherein the elastomeric material is based on at least one thermoplastic elastomer, the at least one thermoplastic elastomer being a block copolymer that includes at least one elastomer block and at least one thermoplastic block.

9. The tread according to claim 8 , wherein the at least one elastomer block of the block copolymer is or are selected from elastomers having a glass transition temperature below 25° C.

10. The tread according to claim 8 , wherein the at least one elastomer block of the block copolymer is or are selected from a group consisting of: ethylene elastomers, diene elastomers, and blends thereof.

11. The tread according to claim 10 , wherein the at least one elastomer block of the block copolymer include a diene elastomer derived from isoprene, or butadiene, or a blend of isoprene and butadiene.

12. The tread according to claim 8 , wherein the at least one thermoplastic block of a block copolymer is or are selected from polymers having a glass transition temperature higher than 80° C. and, if the at least one thermoplastic block includes a semicrystalline thermoplastic block, a melting point higher than 80° C.

13. The tread according to claim 8 , wherein the at least one thermoplastic block of the block copolymer is or are selected from a group consisting of: polyolefins, polyurethanes, polyamides, polyesters, polyacetals, polyethers, phenylene polysulphides, polyfluorides, polystyrenes, polycarbonates, polysulfones, polymethylmethacrylate, polyetherimide, thermoplastic copolymers, and blends thereof.

14. The tread according to claim 8 , wherein the at least one thermoplastic block or blocks of the block copolymer is or are selected from polystyrenes.

15. The tread according to claim 8 , wherein the at least one thermoplastic elastomer is or are selected from a group of thermoplastic elastomers consisting of: styrene/butadiene (SB), styrene/isoprene (SI), styrene/butadiene/isoprene (SBI), styrene/butadiene/styrene (SBS), styrene/isoprene/styrene (SIS), styrene/butadiene/isoprene/styrene (SBIS), and blends of such copolymers.

16. The tread according to claim 8 , wherein the fibre assembly is impregnated with a material that includes at least one plasticizer.

17. The tread according to claim 2 , wherein a dynamic shear modulus G* of the elastomeric material, when subjected to an alternating maximum stress of 0.7 MPa at a frequency of 10 Hz and a temperature of −10° C., is greater than 100 MPa, with greater than 200 MPa being preferable for the dynamic shear modulus G* of the elastomeric material.

18. The tread according to claim 1 , wherein fibres of the fibre assembly are long fibres having a length in excess of 50 mm.

19. The tread according to claim 1 , wherein the fibre assembly is a two-dimensional assembly of fibres.

20. The tread according to claim 19 , wherein the two-dimensional assembly is a nonwoven fibre assembly.

21. The tread according to claim 19 , wherein the two-dimensional assembly is a woven fibre assembly.

22. The tread according to claim 1 , wherein the fibre assembly is a three-dimensional assembly of long fibres having a length in excess of 50 mm.

23. The tread according to claim 22 , wherein the three-dimensional fibre assembly is a felt.

24. The tread according to claim 1 , wherein fibres of the fibre assembly are selected from a group of fibres that includes: textile fibres, mineral fibres, and blends thereof.

25. The tread according to claim 24 , wherein the fibres include fibres selected from a group of fibres that includes: silk fibres, cotton fibres, and wool fibres.

26. The tread according to claim 24 , wherein the fibres are long fibres having a length in excess of 50 mm and include fibres selected from a group that includes: cellulose fibres, polyamide fibres, aramid fibres, polyethylene fibres, polypropylene fibres, polyacrylonitrile fibres, polyimide fibres, polysulfone fibres, polyether sulfone fibres, polyurethane fibres, polyvinyl alcohol fibres, polyester fibres, and polyvinyl chloride fibres.

27. The tread according to claim 26 , wherein the polyester fibres include fibres selected from a group that includes: polyethylene terephthalate fibres, polybutylene terephthalate fibres, and polyethylene naphthalate fibres.

28. The tread according to claim 1 , wherein fibres of the fibre assembly are long fibres and include mineral fibres selected from a group of fibres that includes: glass fibres, carbon fibres, and basalt fibres.

29. The tread according to claim 1 , wherein a thickness of the covering layer is between 0.4

Assignees

• Michelin & Cie
• Michelin Rech Tech

Inventors

• Abad Vincent
• El-Harak Abdeslam
• Perrin Frédéric
• Maesaka Masayuki

Classifications

• B60C11/12

  characterised by the use of narrow slits or incisions, e.g. sipes · CPC title

• B60C1/0016 Primary

  Compositions of the tread · CPC title

• B60C11/1346

  covered by a rubber different from the tread rubber · CPC title

• B60C2011/145

  Discontinuous fibres · CPC title

• B60C11/005 Primary

  with cap and base layers · CPC title