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

• US 9,791,597 B2
• Filed: 07/14/2014
• Issued: 10/17/2017
• Est. Priority Date: 12/27/2007
• Status: Active Grant

• Current Assignee: Essilor International SA
• Original Assignee: Essilor International SA
• Inventors: Zheng, Haipeng
• Primary Examiner(s): Choi, Ling
• Assistant Examiner(s): Wang, Chun-Cheng
• Application Number:
  US14/330,348
• Publication Number:
  US 20140322508A1
• Time in Patent Office: 1,191 Days
• Field of Search: 428447, 428216, 252511
• CPC Class Codes: C03C 17/007 containing a dispersed phase, e.g. particles, fibres or flakes, in a continuous phase
• CPC Class Codes: C03C 17/008 comprising a mixture of materials covered by two or more of the groups C03C17/02, C03C17/06, C03C17/22 and C03C17/28
• CPC Class Codes: C03C 2217/475 Inorganic materials
• CPC Class Codes: C03C 2217/78 Coatings specially designed to be durable, e.g. scratch-resistant
• CPC Class Codes: C08K 3/041 Carbon nanotubes
• CPC Class Codes: C09D 5/00 Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced electrically insulating plastics, resins or waxes H01B3/30; Filling pastes
• CPC Class Codes: C09D 7/61 inorganic
• CPC Class Codes: C09D 7/70 characterised by shape, e.g. fibres, flakes or microspheres
• CPC Class Codes: G02B 1/14 Protective coatings, e.g. hard coatings
• CPC Class Codes: G02B 1/16 having an anti-static effect, e.g. electrically conducting coatings
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

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.

Claims

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_mSi(X)<sub>4-n′

-m</sub> 

 

(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) SiO₂ 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 SiO₂ 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 SiO₂ 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:

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

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_mSi(X)<sub>4-n′

-m</sub> 

 

(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) SiO₂ 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_mSi(X)<sub>4-n′

-m</sub> 

 

(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) SiO₂ 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 μ

m; and

a 50 nm to 2 μ

m 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_mSi(X)<sub>4-n′

-m</sub> 

 

(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) SiO₂ 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 μ

m.