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

Patent metadata

Field	Value
Publication number	US-9791597-B2
Application number	US-201414330348-A
Country	US
Kind code	B2
Filing date	Jul 14, 2014
Priority date	Dec 27, 2007
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

The present invention relates to a curable composition, providing, upon curing, an abrasion-resistant, transparent, antistatic coating, comprising carbon nanotubes and a binder comprising at least one epoxysilane compound, preferably an epoxyalkoxysilane, and optionally fillers such as nanoparticles of non electrically conductive oxides and/or additional binder components such as tetraethoxysilane. The invention further relates to optical articles comprising a substrate, and, starting from the substrate, an abrasion- and/or scratch-resistant coating, and an antistatic coating formed by depositing directly onto said abrasion- and/or scratch-resistant coating the above referred curable composition. The obtained optical articles exhibit antistatic properties, high optical transparency with about 91-92% of transmittance, low haze and improved abrasion resistance.

First claim

The invention claimed is:

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

Assignees

• Essilor Int
• Essilor Int (Compagie Generale D'Optique)

Inventors

• Zheng Haipeng

Classifications

• G02B1/16 Primary

  having an anti-static effect, e.g. electrically conducting coatings · CPC title

• G02B1/14

  Protective coatings, e.g. hard coatings · CPC title

• Y10T428/24975

  No layer or component greater than 5 mils thick · CPC title

• C03C17/008

  comprising a mixture of materials covered by two or more of the groups C03C17/02, C03C17/06, C03C17/22 and C03C17/28 · CPC title

• C03C2217/475

  Inorganic materials · CPC title