Carbon nanotube-based curable coating composition providing antistatic abrasion-resistant coated articles

1. A curable composition, providing, upon curing, an abrasion-resistant, transparent, antistatic coating, wherein the abrasion resistance is characterized by a Bayer value greater than 5, and wherein the coating comprises:

a) carbon nanotubes, and

b) a binder comprising at least one compound of formula:

R n′ Y m Si(X) 4-n′-m   (I)

or a hydrolyzate thereof, in which the R groups are identical or different and represent monovalent organic groups linked to the silicon atom through a carbon atom, the Y groups are identical or different and represent monovalent organic groups linked to the silicon atom through a carbon atom and containing at least one epoxy function, the X groups are identical or different and represent hydrolyzable groups or hydrogen atoms, m and n′ are integers such that m is equal to 1 or 2 and n′+m=1 or 2; and

c) SiO 2 nanoparticles having a diameter of greater than or equal to 25 nm;

wherein the curable composition does not comprise a compound of

R n′ Si(Z) 4-n   (II)

or a hydrolyzate thereof, in which the R groups are identical or different and represent monovalent alkyl groups, the Z groups are identical or different and represent hydrolyzable groups or hydrogen atoms, and n is an integer equal to 0, 1, or 2.

2. The curable composition of claim 1 , wherein the compound of formula I is γ-glycidoxypropyl-trimethoxysilane.

3. The curable composition of claim 1 , wherein the diameter of the SiO 2 nanoparticles is less than or equal to 40 nm.

4. The curable composition of claim 1 , wherein the carbon nanotubes are purified to remove catalyst particles.

5. The curable composition of claim 1 , wherein the carbon nanotubes are in a uniform dispersion.

6. The curable composition of claim 1 , wherein the SiO 2 nanoparticles are in colloidal form.

7. The curable composition of claim 1 further comprising a curing catalyst.

8. The curable composition of claim 7 , wherein the curing catalyst is aluminum acetylacetonate or a hydrolyzate thereof.

9. The curable composition of claim 1 , wherein the Y groups are independently groups of formulae Ill and/or IV:

in which R 2 is an alkyl group or a hydrogen atom, a and c are integers ranging from 1 to 6, and b is 0, 1, or 2.

10. The curable composition of claim 1 , wherein the compound of formula I is an epoxytrialkoxysilane of formula V or VI:

in which R 1 is an alkyl group having 1 to 6 carbon atoms, a and c are integers ranging from 1 to 6, and b is 0, 1 or 2.

11. The curable composition of claim 1 , further comprising a carbon nanotubes stabilizing agent, wherein the stabilizing agent is chosen from octylphenol ethylene oxide condensates.

12. The curable composition of claim 1 , wherein the ratio of (theoretical dry extract weight of nanoparticles)/(theoretical dry extract weight of the composition) is from 25 to 80%.

13. The curable composition of claim 1 , wherein the ratio of (theoretical dry extract weight of compound of formula I)/(theoretical dry extract weight of the composition) is from 20 to 100%.

14. The curable composition of claim 1 , wherein the ratio of (weight of carbon nanotubes)/(theoretical dry extract weight of binder) is from 0.00025 to 0.01.

15. The curable composition of claim 1 , wherein the carbon nanotubes are present in an amount ranging from 0.002 to 0.015% based on the total weight of the composition.

16. A curable composition, providing, upon curing, an abrasion-resistant, transparent, antistatic coating, wherein the abrasion resistance is characterized by a Bayer value greater than 5, and wherein the coating consists of:

a) carbon nanotubes, and

b) a binder comprising at least one compound of formula:

R n′ Y m Si(X) 4-n′-m   (I)

or a hydrolyzate thereof, in which the R groups are identical or different and represent monovalent organic groups linked to the silicon atom through a carbon atom, the Y groups are identical or different and represent monovalent organic groups linked to the silicon atom through a carbon atom and containing at least one epoxy function, the X groups are identical or different and represent hydrolyzable groups or hydrogen atoms, m and n′ are integers such that m is equal to 1 or 2 and n′+m=1 or 2; and

c) SiO 2 nanoparticles having a diameter of greater than or equal to 25 nm;

wherein the curable composition does not comprise a compound of

Rn′Si(Z)4- n   (II)

or a hydrolyzate thereof, in which the R groups are identical or different and represent monovalent alkyl groups, the Z groups are identical or different and represent hydrolyzable groups or hydrogen atoms, and n is an integer equal to 0, 1, or 2.

17. A curable composition, providing, upon curing, an abrasion-resistant, transparent, antistatic coating, wherein the abrasion resistance is characterized by a Bayer value greater than 5, and wherein the coating consists of:

a) carbon nanotubes, and

b) a binder comprising at least one compound of formula:

R n′ Y m Si(X) 4-n′-m   (I)

or a hydrolyzate thereof, in which the R groups are identical or different and represent monovalent organic groups linked to the silicon atom through a carbon atom, the Y groups are identical or different and represent monovalent organic groups linked to the silicon atom through a carbon atom and containing at least one epoxy function, the X groups are identical or different and represent hydrolyzable groups or hydrogen atoms, m and n′ are integers such that m is equal to 1 or 2 and n′+m=1 or 2;

c) SiO 2 nanoparticles having a diameter of greater than or equal to 25 nm;

d) a solvent;

e) a curing catalyst; and

f) a surfactant;

wherein the curable composition does not comprise a compound of

R n′ Si(Z) 4-n   (II)

or a hydrolyzate thereof, in which the R groups are identical or different and represent monovalent alkyl groups, the Z groups are identical or different and represent hydrolyzable groups or hydrogen atoms, and n is an integer equal to 0, 1, or 2.

18. An optical article comprising a substrate, and, starting from the substrate:

a first, silicon-containing, abrasion- and/or scratch-resistant coating having a thickness of at least 1 μm; and

a 50 nm to 2 μm thick antistatic coating formed by depositing directly onto said abrasion- and/or scratch-resistant coating a curable composition comprising:

a) carbon nanotubes, and

b) a binder comprising at least one compound of formula:

R n′ Y m Si(X) 4-n′-m   (I)

or a hydrolyzate thereof, in which the R groups are identical or different and represent monovalent organic groups linked to the silicon atom through a carbon atom, the Y groups are identical or different and represent monovalent organic groups linked to the silicon atom through a carbon atom and containing at least one epoxy function, the X groups are identical or different and represent hydrolyzable groups or hydrogen atoms, m and n′ are integers such that m is equal to 1 or 2 and n′+m=1 or 2; and

c) SiO 2 nanoparticles having a diameter of greater than or equal to 25 nm; and

wherein the optical article is further defined as having a relative light transmission factor in the visible spectrum Tv higher than 90% and a Bayer value greater than 5;

wherein the curable composition does not comprise a compound of

R n′ Si(Z) 4-n   (II)

or a hydrolyzate thereof, in which the R groups are identical or different and represent monovalent alkyl groups, the Z groups are identical or different and represent hydrolyzable groups or hydrogen atoms, and n is an integer equal to 0, 1, or 2.

19. The optical article of claim 18 , wherein the thickness of the antistatic coating is from 100 nm to 1 μm.