NANOPARTICLE SOL-GEL COMPOSITE HYBRID TRANSPARENT COATING MATERIALS

• US 20110003142A1
• Filed: 03/03/2009
• Published: 01/06/2011
• Est. Priority Date: 03/03/2008
• Status: Abandoned Application

• Current Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Original Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Inventors: Sigmund, Wolfgang M., Asuka, Masahiro
• Application Number:
  US12/920,790
• Publication Number:
  US 20110003142A1
• Time in Patent Office: Days
• US Class Current: 428/329
• CPC Class Codes: C08G 77/56 Boron-containing linkages C08G77/485 takes precedence
• CPC Class Codes: C08G 77/58 Metal-containing linkages C08G77/485 takes precedence
• CPC Class Codes: C08K 3/22 of metals
• CPC Class Codes: C08K 3/36 Silica
• CPC Class Codes: C08K 5/5435 containing oxygen in a ring
• CPC Class Codes: C08L 2666/54 Inorganic substances
• CPC Class Codes: C08L 2666/58 SiO2 or silicates
• CPC Class Codes: C09D 183/14 in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms C09D183/10 takes precedence
• CPC Class Codes: C09D 7/61 inorganic
• CPC Class Codes: C09D 7/67 Particle size smaller than 100 nm
• CPC Class Codes: C23C 18/1212 Zeolites, glasses
• CPC Class Codes: C23C 18/122 Inorganic polymers, e.g. silanes, polysilazanes, polysiloxanes
• CPC Class Codes: C23C 18/1254 Sol or sol-gel processing
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/256 Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/257 Iron oxide or aluminum oxide

Abstract

A composite hybrid coating having a thick highly transparent hard coating with excellent barrier properties is described. The hybrid coating is the gelled dispersion of nanoparticles in a sol with least one hydrolyzable silane and at least one hydrolyzable metal oxide precursor. In one embodiment a composite hybrid coating is formed by the curing of a dispersion formed by the addition of a suspension of boehmite nanoplatelets in a sol prepared by the hydrolysis of tetraethoxysilane, γ-glycidoxypropyltrimethoxysilane and titanium tetrabutoxide in ethanol. A plastic substrate can be coated with the dispersion and the dispersion gelled to a thickness of at least 5 μm with heating to less than 150° C.

Claims

1. A transparent composite hybrid coating comprising:

a sol-gel glass wherein said glass is derived from a mixture comprising at least one hydrolyzable silane, wherein at least one of said silanes contains at least one polymerizable organic group attached to the silane, and at least one hydrolyzable metal oxide precursor; and

a plurality of nanoparticles of less than 100 nm in diameter, wherein upon complete cure said coating has a thickness of at least 5 μ

m.

2. The coating of claim 1, wherein said silanes comprise R₍₄₋

n)SiX_n, where;

n is 1 to 4;

X is independently a hydrolyzable group selected from C₁ to C₆ alkoxy, Cl, Br, I, hydrogen, C₁ to C₆ acyloxy, and NR′

R″

where R′ and

R″

are independently H or C₁ to C₆ alkyl, C(O)R′

″

, where R′

″

is independently H, or C₁ to C₆ alkyl; and

R is independently C₁ to C₁₂ radicals, optionally with one or more heteroatoms, including O, S, NH, and NR″

″

where R″

″

is C₁ to C₆ alkyl or aryl, wherein said radical is non-hydrolyzable from said silane and contains a group capable of undergoing polyaddition or polycondensation reactions, selected from Cl, Br, I, unsubstituted or monosubstituted amino, amido, carboxyl, mercapto, isocyanato, hydroxyl alkoxy, alkoxycarbonyl, acyloxy, phosphorous acid, acryloxy, metacryloxy, epoxy, vinyl, alkenyl, or alkynyl.

3. The coating of claim 1, wherein said silanes comprise tetraethoxysilane (TEOS) and γ

-glycidoxypropyltrimethoxysilane (GPTMS).

4. The coating of claim 1, wherein said silane comprises γ

-glycidoxypropyltrimethoxysilane (GPTMS).

5. The coating of claim 1, wherein said metal oxide precursor comprises MX_n where:

n is 2 to 4;

M is a metal selected from the group consisting of Ti, Zr, Al, B, Sn, and V; and

X is a hydrolyzable moiety selected from the group C₁ to C₆ alkoxy, Cl, Br, I, hydrogen, and C₁ to C₆ acryloxy.

6. The coating of claim 1, wherein said metal oxide precursor comprises titanium tetrabutoxide (TTB).

7. The coating of claim 1, wherein said nanoparticles comprise oxides, oxide hydrates, nitrides, or carbides of Si, Al, B, Ti, or Zr in the shape of spheres, needles, or platelets.

8. The coating of claim 1, wherein said nanoparticles comprise SiO₂, TiO₂, ZrO₂, Al₂O₃, Al(O)OH, Si₃N₄ or mixtures thereof.

9. The coating of claim 1, wherein said nanoparticles are from 2 to 50 nm in diameter.

10. The coating of claim 1, wherein said nanoparticles are from 5 to 20 nm in diameter.

11. The coating of claim 1, wherein said nanoparticles comprise boehmite platelets.

12. A method for coating a substrate with a transparent composite hybrid comprising the steps of:

providing a sol derived from a water comprising solution and at least one hydrolyzable silane, wherein at least one of said silanes contains at least one polymerizable organic group attached to said silane;

adding a second solution comprising at least one hydrolyzable metal oxide precursor to said sol;

dispersing a plurality of nanoparticles in said sol to from a dispersion;

coating a substrate with said dispersion; and

gelling said dispersion upon said substrate, wherein said resulting coating is transparent to visible light with a transmittance of at least 85% at a thickness of at least 5 μ

m.

13. The method of claim 12, wherein said silane comprises an alkoxysilane comprising at least one alkoxysilane wherein at least one of said alkoxysilanes has at least one glycidoxypropyl group.

14. The method of claim 12, wherein said silanes comprise tetraethoxysilane (TEAS) and γ

-glycidoxypropyltrimethoxysilane (GPTMS).

15. The method of claim 12, wherein said silane comprises γ

-giycidoxypropyltrimethoxysilane (GPTMS).

16. The method of claim 12, wherein said hydrolyzable metal oxide precursor comprises a metal alkoxide.

17. The method of claim 12, wherein said hydrolyzable metal oxide precursor comprises titanium tetrabutoxide (TTB).

18. The method of claim 12, wherein said nanoparticles comprise boehmite nanoplatelets.

19. The method of claim 12, wherein a solvent in said water comprising solution comprises ethanol.

20. The method of claim 12, wherein said step of dispersing comprises adding a dispersion of said nanoparticle in a solvent.

21. The method of claim 20, wherein said nanoparticles comprise boehmite nanoplatelets and said solvent comprises DMF.

22. The method of claim 12, wherein said step of coating comprises dipping, spreading, brushing, knife coating, rolling, spraying, spin coating, screen printing and curtain coating.

23. The method of claim 12, wherein said step of gelling comprises heating said dispersion coated substrate.

24. The method of claim 23, wherein said heating is to a temperature less than 180°

C.

25. The method of claim 12, wherein said substrate comprises an organic material.

26. The method of claim 25, wherein the organic material comprises a thermoplastic