Fluorescent articles having multiple film layers

• US 20030203211A1
• Filed: 04/30/2002
• Published: 10/30/2003
• Est. Priority Date: 04/30/2002
• Status: Active Grant

• Current Assignee: Avery Dennison Corporation
• Original Assignee: Avery Dennison Corporation
• Inventors: Buoni, Drew J., Wei, Guang-Xue, Dockus, Kimberly A.
• Granted Patent: US 7,264,880 B2
• Time in Patent Office: Days
• US Class Current: 428/412
• CPC Class Codes: B32B 2307/422 Luminescent, fluorescent, phosphorescent
• CPC Class Codes: B32B 2590/00 Signboards, advertising panels, road signs
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/20 using fillers, pigments, thixotroping agents
• CPC Class Codes: B32B 27/308 comprising acrylic (co)polymers
• CPC Class Codes: B32B 27/365 comprising polycarbonates
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet
• CPC Class Codes: G02B 5/128 transparent spheres being embedded in matrix
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]
• CPC Class Codes: Y10T 428/31507 Of polycarbonate
• CPC Class Codes: Y10T 428/31551 Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
• CPC Class Codes: Y10T 428/31786 Of polyester [e.g., alkyd, etc.]
• CPC Class Codes: Y10T 428/31855 Of addition polymer from unsaturated monomers

Abstract

Articles are provided which have fluorescent properties and which are suitable for use in making retroreflective articles such as safety and informational signage. The articles have at least two film layers, each film layer including a colorant dye. The multiple film layer sheeting exhibits excellent resistance to weathering and overall color durability while also providing chromaticity properties dictated by industry standards for a particular coloration. A method of preparing the articles is provided. In a particular application, the articles embody retroreflective properties and are informational for safety signage articles such as pedestrian crossing and school safety fluorescent yellow green signs.

Claims

1. An article comprising:

an underlayer colored fluorescent film having a first fluorescent dye within an underlayer polymer matrix;

an overlayer colored fluorescent film having a second fluorescent dye within an overlayer polymer matrix, said overlayer colored fluorescent film has greater UV light stability than said underlayer colored film;

the article has said overlayer colored fluorescent film over said underlayer colored fluorescent film; and

said article has a selected fluorescent coloration different from both said underlayer colored fluorescent film and said overlayer colored fluorescent film.

2. The article in accordance with claim 1, wherein said underlayer polymer matrix has a polymer structure selected from the group consisting of that of an acrylic resin, a polycarbonate, a polyester, a polyarylate, a copolyestercarbonate, a polystyrene, a styrene-acrylonitrile copolymer, a polyurethane, a polyvinyl chloride, and combinations and copolymers thereof.

3. The article in accordance with claim 1, wherein said overlayer polymer matrix has a polymer structure selected from the group consisting of that of an acrylic resin, a polyarylate resin, a copolyestercarbonate resin, and combinations and copolymers thereof.

4. The article in accordance with claim 1, wherein said overlayer polymer matrix had been formed from an acrylic resin.

5. The article in accordance with claim 1, wherein said selected fluorescent coloration of the article is selected from the group consisting of fluorescent yellow green, fluorescent yellow, fluorescent orange, fluorescent red, fluorescent blue and fluorescent green as provided by dyes selected from the group consisting of benzoxanthenes, benzothiazines, perylenes, perylene imides, pereylene esters, thioxanthenes, and thioindigoids.

6. The article in accordance with claim 1, wherein said selected fluorescent coloration is fluorescent yellow green having “

x” and

“

y”

chromatcity coordinates which are bounded by the following “

x” and

“

y”

chromaticity coordinates;

(x=0.387, y=0.610), (x=0.460, y=0.540), (x=0.421, y=0.486) and (x=0.368, y=0.539).

7. The article in accordance with claim 1, wherein said overlayer colored fluorescent film has UV screening properties in excess of those of the underlayer polymer.

8. The article in accordance with claim 1, wherein said second fluorescent dye has a greater daytime luminance factor “

Y%”

than said first dye.

9. The article in accordance with claim 1, wherein said overlayer colored fluorescent film has greater light absorbing ability than said underlayer colored film, whereby color durability and UV light degradation protection for the article are enhanced when compared with the color durability and UV protection of either individual outerlayer or underlayer colored film.

10. The article in accordance with claim 1, wherein said first dye is more light fast in said underlayer film than in said overlayer film.

11. The article in accordance with claim 1, wherein said underlayer film is less brittle than said overlayer film.

12. The article in accordance with claim 4, wherein said underlayer film is less brittle than said overlayer film.

13. The article in accordance with claim 1, wherein said article includes retroreflective members.

14. The article in accordance with claim 13, wherein said underlayer is between said overlayer and said retroreflective members such that incident light passes through said overlayer, then passes into said underlayer, then encounters said retroflective member and retroreflects into said underlayer colored film and passes through said overlayer colored film and out of the article.

15. The article in accordance with claim 14, wherein said retroreflective members are formed into said underlayer.

16. The article in accordance with claim 14, wherein said retroreflective members are prismatic members.

17. The article in accordance with claim 14, wherein said retroreflective members are arranged to provide an encapsulated lens construction.

18. The article in accordance with claim 14, wherein said retroreflective members are arranged to provide an enclosed lens construction.

19. The article in accordance with claim 1, wherein said article is signage which is suitable for outdoor use for at least three years.

20. The article in accordance with claim 1, wherein said article is signage which is suitable for outdoor use for at least three years, and the overlayer film and underlayer film combine to provide yellow green coloration within the box defined by the following “

x” and

“

y”

chromaticity coordinates;

(x=0.387, y=0.610), (x=0.460, y=0.540), (x=0.421, y=0.486) and (x=0.368, y=0.539).

21. The article in accordance with claim 1, wherein said fluorescent dye of the overlayer is a benzoxanthene dye.

22. The article in accordance with claim 1, wherein said fluorescent dye of the underlayer is a benzothiazine dye.

23. The article in accordance with claim 1, wherein said underlayer polymer matrix is a polycarbonate, the fluorescent dye of said underlayer film is a benzothiazine dye, said overlayer polymer matrix is an acrylic resin, and said fluorescent dye of the overlayer is a benzoxanthene dye.

24. The article in accordance with claim 1, wherein said underlayer polymer matrix is an acrylic resin, the fluorescent dye of said underlayer film being selected from the group consisting of a thioxanthene dye and a perylene dye, said overlayer polymer matrix is an acrylic resin, and said fluorescent dye of the overlayer is a benzoxanthene dye.

25. The article in accordance with claim 1, wherein said underlayer polymer matrix is an acrylic resin, the fluorescent dye of said underlayer film being a perylene dye, said overlayer polymer matrix is an acrylic resin, and said fluorescent dye of the overlayer is a benzoxanthene dye.

26. The article in accordance with claim 4, wherein the second fluorescent dye of the overlayer is a perylene dye.

27. The article in accordance with claim 1, wherein said underlayer polymer matrix is a polyarylate resin, the fluorescent dye of said underlayer film being a thioxanthone, thioindigoid, thioxanthene, perylene, coumarin or lactone.

28. The article in accordance with claim 1, wherein said underlayer polymer matrix is a copolyestercarbonate resin, the fluorescent dye of said underlayer film being a thioxanthone, thioindigoid, thioxanthene, perylene, coumarin or lactone.

29. The article in accordance with claim 1, wherein said overlayer polymer matrix is a polyarylate resin, the fluorescent dye of said overlayer film being a thioxanthone, thioindigoid, thioxanthene, perylene, coumarin or lactone.

30. The article in accordance with claim 1, wherein said overlayer polymer matrix is a copolyestercarbonate resin, the fluorescent dye of said overlayer film being a thioxanthone, thioindigoid, thioxanthene, perylene, coumarin or lactone.

31. The article in accordance with claim 1, further including a cap layer polymeric film overlying said overlayer colored fluorescent film, said cap layer having properties selected from the group consisting of abrasion resistance, graffiti resistance, dew resistance, and combinations thereof.

32. The article in accordance with claim 1, further including a cap layer film polymethyl methacrylate matrix, said cap layer providing UV light screening properties, and said overlayer is between said underlayer and said cap layer.

33. The article in accordance with claim 1, wherein said overlayer film absorbs substantial amounts of light in a substantial portion of a light spectrum between about 250 nm and about 450 nm.

34. The article in accordance with claim 1, wherein the article has a Δ

E* value after extended exposure to outdoor conditions which is substantially less than that of either said underlayer film or of said overlayer film.

35. The article in accordance with claim 1, wherein said article is a yellow green fluorescent article, said underlayer polymer matrix is a polycarbonate, said first fluorescent dye is Huron Yellow D417 benzothiazine dye, said overlayer polymer matrix is a polymethyl methacrylate matrix, and said second fluorescent dye is Lumofast Yellow 3G benzoxanthene dye.

36. The article in accordance with claim 1, further including a light stabilizer selected from the group consisting of a UV absorber, a HALS component and combinations thereof, said light stabilizer being within either or both of said underlayer and said overlayer.

37. The article in accordance with claim 1, wherein said first fluorescent dye is different from said second fluorescent dye.

38. The article in accordance with claim 1, wherein said underlayer colored fluorescent film and overlayer colored fluorescent film each are individually unsuitable to meet UV light durability requirements and coloration compliance standards for outdoor signage having said selected fluorescent coloration, while said article meets said requirements and standards.

39. An article having fluorescent coloration, comprising:

an underlayer colored film having a first dye within an underlayer polymer matrix;

an overlayer colored film having a second dye within an overlayer polymer matrix, said overlayer polymer matrix having been formed from an acrylic resin, a polyarylate resin, a copolyestercarbonate, or combinations or copolymers thereof;

said overlayer colored film overlies said underlayer colored film; and

said first dye and said second dye are different from each other, the article has a selected fluorescent coloration different from the coloration of either said underlayer colored film or said overlayer colored film, and said overlayer colored film exhibits UV light screening properties in excess of any light screening properties of said underlayer colored film.

40. The article in accordance with claim 39, wherein said underlayer polymer matrix has a polymer structure selected from the group consisting of that of an acrylic resin, a polycarbonate, a polyester, a polyarylate, a copolyestercarbonate, a polystyrene, a styrene-acrylonitrile copolymer, a polyurethane, a polyvinyl chloride, and combinations and copolymers thereof.

41. The article in accordance with claim 39, wherein said selected fluorescent coloration is fluorescent yellow green having the following “

x” and

“

y”

chromaticity coordinates which are bounded by the following “

x” and

“

y”

chromaticity coordinates;

(x=0.387, y=0.610), (x=0.460, y=0.540), (x=0.421, y=0.486) and (x=0.368, y=0.539).

42. The article in accordance with claim 39, wherein said overlayer colored film has greater UV light stability than said underlayer colored film.

43. The article in accordance with claim 39, further including a cap layer film of an acrylic resin, a polyarylate resin, a copolyestercarbonate resin, or combinations or copolymers thereof, said cap layer providing UV light screening properties, and said cap layer overlies said overlayer.

44. The article in accordance with claim 39, wherein said first dye is more light fast in said underlayer film than in said overlayer film.

45. The article in accordance with claim 39, wherein said underlayer film is less brittle than said overlayer film.

46. The article in accordance with claim 39, wherein said article includes retroreflective members, and said underlayer is between said overlayer and said retroreflective members such that incident light passes through said overlayer, then passes into said underlayer, then encounters said retroflective member and retroreflects into said underlayer colored film and passes through said overlayer colored film and out of the article.

47. The article in accordance with claim 46, wherein said retroreflective members are formed into said underlayer.

48. The article in accordance with claim 46, wherein said retroreflective members are prismatic members.

49. The article in accordance with claim 46, wherein said retroreflective members are arranged to provide an encapsulated lens construction.

50. The article in accordance with claim 46, wherein said retroreflective members are arranged to provide an enclosed lens construction.

51. The article in accordance with claim 39, wherein said article is signage which is suitable for outdoor use for at least three years.

52. The article in accordance with claim 39, wherein said article is signage which is suitable for outdoor use for at least three years, and the overlayer film and underlayer film combined to provide yellow green coloration within the box defined by following “

x” and

“

y”

chromaticity coordinates;

(x=0.387, y=0.610),(x=0.460, y=0.540), (x=0.421, y=0.486) and (x=0.368, y=0.539).

53. The article in accordance with claim 39, wherein said fluorescent dye of the overlayer is a benzoxanthene dye.

54. The article in accordance with claim 53, wherein said fluorescent dye of the underlayer is a benzothiazine dye.

55. The article in accordance with claim 39, wherein said underlayer colored film and overlayer colored film each are individually unsuitable to meet UV light durability requirements and coloration compliance standards for outdoor signage having said selected fluorescent coloration, while said article meets said requirements and standards.

56. A method of manufacturing a fluorescent colored retroreflective sheeting, comprising:

combining a first polymer resin and a first dye into an underlayer formulation;

formulating a second polymer resin and a second dye into an overlayer formulation;

forming said underlayer formulation into an underlayer colored film, forming said overlayer formulation into an overlayer colored film, said overlayer colored film has greater UV light stability than said underlayer colored film, at least one of said colored films being a fluorescent colored film; and

placing said overlayer colored film onto said underlayer colored film to provide a multiple layered fluorescent sheeting having a selected fluorescent coloration.

57. The method in accordance with claim 56, further including adding retroreflective elements so that said underlayer colored film is between the overlayer colored film and the retroreflective elements.

58. The method in accordance with claim 56, further including placing a polymeric cap layer onto said overlayer colored film such that said overlayer colored film is between said cap layer and said underlayer colored film.