High refractive index, durable hard coats

• US 20060147702A1
• Filed: 12/30/2004
• Published: 07/06/2006
• Est. Priority Date: 12/30/2004
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Kolb, Brant U., Pokorny, Richard J., Olson, David B., Mader, Roger A.
• Granted Patent: US 7,491,441 B2
• Time in Patent Office: Days
• US Class Current: 428/328
• CPC Class Codes: C08F 222/102 of dialcohols, e.g. ethylene glycol di(meth)acrylate or 1,4-butanediol dimethacrylate
• CPC Class Codes: C08F 290/06 Polymers provided for in subclass C08G
• CPC Class Codes: C08F 290/061 Polyesters; Polycarbonates
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 53/00 Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 53/005 Modified block copolymers
• CPC Class Codes: C09D 4/00 Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
• 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 428/31935 Ester, halide or nitrile of addition polymer

Abstract

The development of new compositions and new aromatic sulfur acrylate monomers results in improved hardcoat films, and improved optical films that contain the hard coat films. The films provide improved display systems when incorporated thereon. The combination of functionalized zirconia nanoparticles with multifunctional acrylate crosslinkers and high index of refraction aromatic sulfur acrylates, about 1.58 or greater, produces abrasion resistant hard coats that have relatively high refractive indices.

Claims

1. A display system comprising a hard coat formed from a substantially transparent substrate, the hard coat further comprising:

functionalized zirconia nanoparticles;

at least one acrylate crosslinking agent; and

a least one aromatic sulfur acrylate monomer containing a naphthalenic group or more than one aromatic group.

2. The display system of claim 1 wherein said aromatic sulfur acrylate monomer is selected from the group of compounds defined by the following naphthalenic and phenylic formulas:

3. The display system of claim 1 wherein said acrylate crosslinking agent is multifunctional and said aromatic sulfur acrylate exhibits an index of refraction of at least 1.58 or greater.

4. The display system of claim 2 wherein said aromatic sulfur acrylate monomer is selected from the group consisting of acrylic acid 2-[7-(2-acryloyloxy-ethylsulfanyl)-naphthalen-2-ylsulfanyl]-ethyl ester and acrylic acid 2-{4-[4-(2-acryloyloxy-ethylsulfanyl)-phenylsulfanyl]-phenylsulfanyl}-ethyl ester.

5. The display system of claim 1 wherein said aromatic sulfur acrylate monomer is selected from the group of compounds defined by the following formula:

6. The display system of claim 5 wherein said aromatic sulfur acrylate is selected from the group consisting of acrylic acid 2-acryloyloxymethyl-3-(naphthalene-2-ylsulfanyl)-2-(naphthalene-2-ylsulfanylmethyl)-propyl ester and acrylic acid 2-acryloyloxymethyl-3-phenylsulfanyl-2-phenylsulfanylmethyl-propyl ester.

7. A coating comprising:

an first layer formed from a resin substrate; and

a second hardcoat layer formed from a composition comprising a surface modified inorganic nanoparticle, at least one acrylate crosslinking agent, and an aromatic sulfur acrylate, said second hardcoat layer coupled to said first layer; and

an optional third layer formed from a material having a relatively low refractive index, said third layer coupled to said second hardcoat layer.

8. A display system comprising the antireflective coating of claim 7.

9. The antireflective coating of claim 7 wherein said inorganic nanoparticle is surface modified zirconia.

10. The coating of claim 7 wherein said third layer has a refractive index no greater than 1.5.

11. The coating of claim 7 wherein said second layer has a refractive index of at least 1.58.

12. A hard coat comprising:

an aromatic sulfur acrylate and surface modified zirconia nanoparticles within a resin matrix, wherein said hard coat has a refractive index of at least 1.58.

13. A display system comprising the hard coat of claim 12.

14. An antireflective coating containing the hard coat of claim 12.

15. The hard coat of claim 12 crosslinked with an acrylate crosslinker.

16. The hard coat of claim 12 further comprising a photoinitiator.

17. The hard coat of claim 12 wherein said hard coat has an abrasion resistance no greater than 3.0% haze as determined by modified ASTM F 735-94.

18. The hard coat of claim 12 wherein said resin matrix comprises pentaerythritol triacrylate a multifunctional acrylate with a functionality of at least 3.

19. The hard coat of claim 18 wherein said multifunctional acrylate is pentaerythritol triacrylate.

20. A coating composition containing a resin substrate, the coating composition comprising:

an aromatic sulfur acrylate containing a naphthalenic group or more than one aromatic group;

an acrylate crosslinker; and

functionalized zirconia nanoparticles.

21. The composition of claim 20 wherein said zirconia nanoparticles have a diameter measuring about 10-30 nanometers.

22. An aromatic sulfur acrylate monomer defined by the formula:

23. The monomer of claim 22 selected from the group consisting of acrylic acid 2-acryloyloxymethyl-3-(naphthalene-2-ylsulfanyl)-2-(naphthalene-2-ylsulfanylmethyl)-propyl ester and acrylic acid 2-acryloyloxymethyl-3-phenylsulfanyl-2-phenylsulfanylmethyl-propyl ester.

24. An aromatic sulfur acrylate monomer defined by the following formulae:

25. A polymerizable composition comprising a sulfur acrylate monomer selected from the group defined by the following formulae: