IN-SITU NANOPARTICLE FORMATION IN POLYMER CLEARCOATS

• US 20090022995A1
• Filed: 07/16/2007
• Published: 01/22/2009
• Est. Priority Date: 07/16/2007
• Status: Active Grant

• Current Assignee: University of Kentucky
• Original Assignee: University of Kentucky
• Inventors: Khatri, Rajesh, Graham, Uschi Ursula M., Davis, Burt H.
• Granted Patent: US 8,197,901 B2
• Time in Patent Office: Days
• US Class Current: 428/409
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 33/12 Silica; Hydrates thereof, e.g. lepidoic silicic acid
• CPC Class Codes: C01G 23/047 Titanium dioxide
• CPC Class Codes: C01G 7/00 Compounds of gold
• CPC Class Codes: C01P 2004/04 obtained by TEM, STEM, STM or AFM
• CPC Class Codes: C01P 2004/24 Nanoplates, i.e. plate-like particles with a thickness from 1-100 nanometer
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2006/60 Optical properties, e.g. expressed in CIELAB-values
• CPC Class Codes: C08K 3/08 Metals
• CPC Class Codes: C08K 3/22 of metals
• CPC Class Codes: C09D 5/38 Paints containing free metal not provided for above in groups C09D5/00 - C09D5/36
• CPC Class Codes: C09D 7/48 Stabilisers against degradation by oxygen, light or heat
• CPC Class Codes: C09D 7/67 Particle size smaller than 100 nm
• CPC Class Codes: Y10T 428/31 Surface property or characteristic of web, sheet or block
• CPC Class Codes: Y10T 428/31507 Of polycarbonate
• CPC Class Codes: Y10T 428/31511 Of epoxy ether
• CPC Class Codes: Y10T 428/31551 Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane
• CPC Class Codes: Y10T 428/31725 Of polyamide
• CPC Class Codes: Y10T 428/31786 Of polyester [e.g., alkyd, etc.]
• CPC Class Codes: Y10T 428/31938 : Polymer of monoethylenically unsaturated hydrocarbon
• CPC Class Codes: Y10T 428/31942 : Of aldehyde or ketone condensation product

Abstract

Methods and compositions for forming a transparent clear coat characterized by a desired property, such as a color effect, resistance to UV light-induced degradation and/or scratch resistance, on a substrate are detailed according to embodiments of the present invention. Particular compositions and methods for producing a transparent clear coat layer include nanoparticles formed in-situ during curing of a transparent clear coat. Curable clear coat compositions are described according to embodiments of the present invention which include one or more substantially dissolved nanoparticle precursors.

Claims

1. A method of forming a transparent coating on a substrate, the transparent coating having a color effect, resistance to UV light-induced degradation and/or scratch resistance, comprising:

applying a curable clear coat composition comprising a first nanoparticle precursor, wherein the curable clear coat composition comprising a first nanoparticle precursor is substantially free of undissolved first nanoparticle precursor; and

curing the curable clear coat composition to form a transparent coating comprising a polymer and a plurality of in-situ formed nanoparticles having an average particle size in the range of about 1-100 nanometers, inclusive, wherein the plurality of nanoparticles confers a color effect, resistance to UV light-induced degradation and/or scratch resistance to the transparent coating.

2. The method of claim 1, wherein at least a portion of the plurality of nanoparticles is characterized by a plasmon resonance absorption in the visible range.

3. The method of claim 1, wherein the first nanoparticle precursor is a metal salt.

4. The method of claim 1, wherein the plurality of nanoparticles is a plurality of nanoparticles characterized by an amount of elemental metal in the range of about 95-100% of the total weight of the plurality of nanoparticles and wherein the plurality of nanoparticles confers a color effect to the transparent coating.

5. The method of claim 1, wherein the first nanoparticle precursor is HAuCl₄.

6. The method of claim 1, wherein the first nanoparticle precursor comprises a metal salt capable of being reduced under curing conditions to elemental metal.

7. The method of claim 1, wherein the first nanoparticle precursor comprises a metal selected from the group consisting of:

Au, Ag, Bi, Cr, Co, Cu, Fe, Mn, Ni, Pt, Sb, Se and Sn.

8. The method of claim 1, wherein the first nanoparticle precursor is a metal salt capable of forming a metal oxide under curing conditions.

9. The method of claim 1, wherein the first nanoparticle precursor is a silicate.

10. The method of claim 1, wherein the plurality of nanoparticles is a plurality of nanoparticles characterized by an amount of a metal oxide in the range of about 95-100% of the total weight of the plurality of nanoparticles and wherein the plurality of nanoparticles confers scratch resistance and/or resistance to UV light-induced degradation to the transparent coating.

11. The method of claim 10, wherein the metal oxide is selected from the group consisting of:

alumina, silica, ceria, titania, an iron oxide, and a combination thereof.

12. The method of claim 1, wherein the curable clear coat composition further comprises a second nanoparticle precursor.

13. The method of claim 12, wherein the first nanoparticle precursor is HAuCl₄ and the second nanoparticle precursor comprises a metal selected from the group consisting of:

Al, Au, Ag, Bi, Ce, Cr, Co, Cu, Fe, Mn, Ni, Pt, Sb, Se, Si, Sn and Ti.

14. The method of claim 12, wherein the first nanoparticle precursor is HAuCl₄ and the second nanoparticle precursor is selected from the group consisting of:

selenium chloride, tin chloride, iron nitrate, antimony acetate, nickel nitrate, copper nitrate, cobalt nitrate, chromium nitrate, manganese nitrate, bismuth citrate, aluminum nitrate, tetramethylorthosilicate, titanium tetrabutoxide, and combinations thereof.

15. The method of claim 12, wherein the second nanoparticle precursor is substantially dissolved in the curable clear coat composition.

16. The method of claim 1, wherein the curable clear coat composition is substantially free of nanoparticles.

17. The method of claim 1, wherein the nanoparticles are substantially uniformly dispersed throughout the transparent coating.

18. The method of claim 1, wherein the curable clear coat composition comprises a metal salt nanoparticle precursor and a metal oxide nanoparticle precursor, wherein the transparent coating comprises a plurality of metal oxide nanoparticles and a plurality of elemental metal nanoparticles, and wherein the transparent coating is characterized by a color effect and by resistance to UV light-induced degradation and/or scratch resistance.

19. A composition for forming a transparent coating layer on a substrate, the transparent coating having a color effect, resistance to UV light-induced degradation and/or scratch resistance, comprising:

a curable clear coat material having a first nanoparticle precursor substantially dissolved therein.

20. The composition of claim 19, further comprising a second nanoparticle precursor.

21. The composition of claim 19, wherein the first nanoparticle precursor is a metal salt.

22. The composition of claim 19, wherein the first nanoparticle precursor is HAuCl₄.

23. The composition of claim 21, wherein the metal salt comprises a metal selected from the group consisting of:

Al, Au, Ag, Bi, Ce, Cr, Co, Cu, Fe, Mn, Ni, Pt, Sb, Se, Sn and Ti.

24. The composition of claim 19, wherein the first nanoparticle precursor is a silicate.

27. The substrate of claim 22, wherein the substrate is an automotive body panel.

28. The substrate of claim 22, wherein the substrate comprises a multilayer laminate, the multilayer laminate comprising at least an innermost primer layer adjacent the substrate and an outermost coating layer, wherein the transparent coating is the outermost layer.

25. A composition for forming a transparent coating layer on a substrate, the transparent coating having a color effect, resistance to UV light-induced degradation and/or scratch resistance, comprising:

a curable clear coat material comprising a first nanoparticle precursor, wherein the precursor comprises a metal selected from the group consisting of;

Al, Au, Bi, Ce, Cr, Co, Cu, Fe, Mn, Ni, Pt, Sb, Se, Sn and Ti.

26. An article comprising a substrate having a transparent coating on at least one surface of the substrate, wherein the transparent coating comprises a cured clear coat polymer and a plurality of in-situ formed nanoparticles, and wherein the transparent coating confers a color effect, resistance to UV light-induced degradation and/or scratch resistance to the substrate.

29. Use of a curable clear coat composition for forming a transparent coating layer on a substrate, the transparent coating having a color effect, resistance to UV light-induced degradation and/or scratch resistance, wherein the curable clear coat composition comprises:

a nanoparticle precursor.