Tyre for vehicle wheels

Patent metadata

Field	Value
Publication number	US-12031035-B2
Application number	US-202117455165-A
Country	US
Kind code	B2
Filing date	Nov 16, 2021
Priority date	Dec 13, 2016
Publication date	Jul 9, 2024
Grant date	Jul 9, 2024

Abstract

The present invention relates to a tyre for vehicle wheels comprising at least one structural element comprising a cross-linked elastomeric material obtained by cross-linking a cross-linkable elastomeric composition comprising carbon nanotubes, wherein said carbon nanotubes are obtained with an iron oxides and/or aluminium oxides based catalyst substantially free of Co, Ni and Mo.

First claim

The invention claimed is:

1. An iron oxide and/or aluminium oxide catalyst substantially free of Co, Ni, and Mo, obtained by a process comprising:
preparing an aqueous solution (i) comprising a Fe3+ soluble salt and an Al3+ soluble salt, wherein the solution (i) comprises a molar concentration of Fe3+ ranging from 0.3 to 1.5 M and a molar concentration of Al3+ ranging from 0.8 to 2.4 M,
preparing an aqueous solution (ii) comprising ammonium hydroxide, wherein the solution (ii) comprises a molar concentration of NH3 ranging from 1.8 to 18 M,
adding solution (ii) to solution (i), wherein an amount of NH3 added per minute ranges from 1.3.10-4 to 4.5.10-1 moles per total moles of iron or aluminium or both iron and aluminium, resulting in a combined solution with a pH ranging from 6 to 8, wherein a gel of the combined solution forms,
drying the gel at a temperature ranging from 35° C. to 100° C. to obtain a solid, and
calcining the obtained solid at a temperature ranging from 250° C. to 750° C. under an atmosphere chosen from air and nitrogen,
wherein the catalyst comprises a grain size, expressed as average surface equivalent spherical diameter, ranging from 10 to 150 μm, an apparent density ranging from 0.300 to 0.900 g/cm 3 , and a surface area ranging from 50 to 500 m 2 /g.

2. The catalyst according to claim 1 , further comprising a nominal iron content (normalizing the formulation as Fe+Al 2 O 3 ) higher than 30% by weight.

3. The catalyst according to claim 2 , wherein the nominal iron content is equal to or higher than 35% by weight, or equal to or higher than 45% by weight.

4. A process for preparing carbon nanotubes comprising:
loading a catalyst according to claim 1 on a porous material in a reactor chamber,
bringing a temperature of the reactor chamber to a reaction temperature, and
fluxing a gaseous stream of one or more gaseous hydrocarbons in the reactor chamber.

5. A carbon nanotube according to the process of claim 4 , comprising an amount of Co, Ni, and Mo lower than 0.1 ppm, and a carbon:residual catalyst (C/r) weight ratio higher than 10:1.

6. The carbon nanotube according to claim 5 , wherein the amount of Co, Ni, and Mo is lower than 0.01 ppm, or lower than 0.001 ppm.

7. The carbon nanotube according to claim 5 , wherein the carbon:residual catalyst (C/r) weight ratio is higher than 20:1, higher than 40:1, or higher than 50:1.

8. A tyre for vehicle wheels comprising:
at least one structural element with a cross-linked elastomeric material,
wherein the crosslinked elastomeric material comprises, before vulcanization, a cross-linkable elastomeric composition comprising carbon nanotubes according to claim 5 from a carbon source and iron oxide and/or aluminium oxide catalysts substantially free of Co, Ni, and Mo.

9. The tyre according to claim 8 , wherein the tyre comprises at least one carcass structure having opposite lateral edges associated with respective reinforcing annular structures, a belt structure applied in a radially external position with respect to the at least one carcass structure, a tread band applied in a radially external position with respect to the at least one carcass structure, and a pair of sidewalls laterally applied on opposite sides with respect to the at least one carcass structure.

10. The tyre according to claim 8 , wherein the structural element is chosen from a tread band, a tread underlayer, a sidewall, a mini-sidewall, a sidewall insert, a bead structure, a rubber coating of the at least one carcass structure, and a rubber coating of the belt structure.

11. The tyre according to claim 8 , wherein the cross-linkable elastomeric composition comprises an amount of carbon nanotubes ranging from 0.5 to 5 phr.

12. The tyre according to claim 11 , wherein the amount of carbon nanotubes ranges from 1 to 4 phr, or from 2 to 3 phr.

13. The tyre according to claim 8 , wherein the carbon nanotubes comprise a carbon percentage equal to or higher than 90% by weight, with respect to the total weight of the carbon nanotubes.

14. The tyre according to claim 13 , wherein the carbon percentage is equal to or higher than 95% by weight, equal to or higher than 97% by weight, or equal to or higher than 98% by weight, with respect to the total weight of the carbon nanotubes.

15. The tyre according to claim 8 , wherein the carbon nanotubes comprise a residual catalyst percentage lower than 10% by weight, with respect to the total weight of the carbon nanotubes.

16. The tyre according to claim 15 , wherein the residual catalyst percentage is lower than 5% by weight, lower than 3% by weight, or lower than 2% by weight, with respect to the total weight of the carbon nanotubes.

17. The tyre according to claim 8 , wherein the carbon nanotubes are characterised by a carbon:residual catalyst (C/r) weight ratio higher than 10:1.

18. The tyre according to claim 17 , wherein the carbon:residual catalyst (C/r) weight ratio is higher than 20:1, higher than 40:1, or higher than 50:1.

19. The tyre according to claim 8 , wherein the carbon nanotubes comprise an amount of Co, Ni, and Mo lower than 0.1 ppm.

20. The tyre according to claim 19 , wherein the amount of Co, Ni, and Mo is lower than 0.01 ppm, or lower than 0.001 ppm.

Assignees

• Pirelli
• Milano Politecnico

Inventors

• Mazzocchia Carlo Vittorio
• Daghetta Matteo Antonio
• Pellegrino Lorenzo
• Citterio Attillio
• Albizzati Enrico
• Giannini Luca
• Hanel Thomas

Classifications

• C08L2312/00

  Crosslinking · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• B60C1/0025

  Compositions of the sidewalls · CPC title

• B60C1/0016

  Compositions of the tread · CPC title

• B01J37/08

  Heat treatment {(B01J37/0009, B01J37/0018 take precedence)} · CPC title