Retroreflective articles including optically active areas and optically inactive areas

Patent metadata

Field	Value
Publication number	US-9618663-B2
Application number	US-201013641271-A
Country	US
Kind code	B2
Filing date	Apr 15, 2010
Priority date	Apr 15, 2010
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

This disclosure generally relates to retroreflective articles and methods of making such articles.

First claim

What is claimed is:

1. A retroreflective article, comprising:
a retroreflective layer including multiple cube corner elements that collectively form a structured surface that is opposite a major surface; and
a sealing layer having a first region and a second region, wherein the second region is in contact with the structured surface and wherein the second region surrounds the first region to form at least one cell with a cell size; and
wherein the sealing layer includes a barrier layer disposed within the first region between the sealing layer and the retroreflective layer separating a low refractive index layer from the sealing layer;
wherein the low refractive index layer is between the barrier layer of the first region and the structured surface of the retroreflective layer, wherein the first region has a cell size that is less than 1000 microns; and
wherein the CAP-Y is greater than 55.

2. The retroreflective article of claim 1 , wherein the cell size for the first region is less than 750 microns.

3. The retroreflective article of claim 1 , further including a seal leg that defines the first region.

4. The retroreflective article of claim 1 , wherein the retroreflective article exhibits a total light return that is not less than about 5% for incident visible light at an entrance angle of −4 degrees.

5. The retroreflective article of claim 1 , wherein the retroreflective article exhibits a coefficient of retroreflection R A that is not less than about 40 cd/(lux·m 2 ) for an observation angle of 0.2 degrees and an entrance angle of −4 degrees.

6. The retroreflective article of claim 1 , wherein the retroreflective article exhibits a coefficient of retroreflection R A that is not less than about 8 cpl for an observation angle of 2.0 degrees and an entrance angle of −4 degrees.

7. The retroreflective article of claim 1 , wherein the retroreflective article exhibits a % R T slope that is not less than about 3%/degree for an entrance angle of −4 degrees and an observation angle of 2 degrees.

8. The retroreflective article of claim 1 , wherein the retroreflective article exhibits a coefficient of retroreflection R A that is not less than about 4 cpl for an observation angle of 3.0 degrees and an entrance angle of −4 degrees.

9. The retroreflective article of claim 1 , wherein the retroreflective article exhibits a % R T slope that is not less than about 1.5%/degree for an entrance angle of −4 degrees and an observation angle of 3 degrees.

10. The retroreflective article of claim 1 , wherein less than about 65% of the structured surface is retroreflective.

11. The retroreflective article of claim 1 , wherein the cube corner elements are truncated cube corner elements.

12. The retroreflective article of claim 1 , wherein the sealing layer has a first region and a second region and wherein the second region is raised relative to the first region and is in contact with the structured surface.

13. The retroreflective article of claim 1 , wherein the retroreflective article exhibits a coefficient of retroreflection RA that is not less than about 40 cd/(lux m 2 ) for an observation angle of 0.2 degrees and an entrance angle of −4 degrees.

14. The retroreflective article of claim 1 , wherein the retroreflective article exhibits a coefficient of retroreflection RA that is not less than about 20 cpl for an observation angle of 1.0 degrees and an entrance angle of −4 degrees.

15. The retroreflective article of claim 1 , wherein the retroreflective article exhibits a % R T slope that is not less than about 9% degree for an entrance angle of −4 degrees and an observation angle of 1 degree.

16. The retroreflective article of claim 1 , wherein the retroreflective article exhibits a coefficient of retroreflection RA that is not less than about 8 cpl for an observation angle of 2.0 degrees and an entrance angle of −4 degrees.

17. The retroreflective article of claim 1 , wherein the retroreflective article exhibits a % R T slope that is not less than about 3%/degree for an entrance angle of −4 degrees and an observation angle of 2 degrees.

18. The retroreflective article of claim 1 , wherein the retroreflective article exhibits a % R T slope that is not less than about 1.5%/degree for an entrance angle of −4 degrees and an observation angle of 3 degrees.

19. The retroreflective article of claim 1 , comprising numerous cells that form one of an irregular pattern, a random pattern, a regular pattern, a grid, words, graphics, images, lines, and intersecting zones and wherein the distance between cells provides an angle of 1 arc minute or less when viewed at 20 feet.

Assignees

• Smith Kenneth L
• Free Michael Benton
• Thakkar Bimal V
• Chiu Raymond C
• 3M Innovative Properties Co

Inventors

• Smith Kenneth L
• Free Michael Benton
• Thakkar Bimal V
• Chiu Raymond C

Classifications

• B32B2307/75

  Printability · CPC title

• B32B27/322

  comprising halogenated polyolefins, e.g. PTFE · CPC title

• B32B2255/20

  Inorganic coating · CPC title

• B32B27/34

  comprising polyamides · CPC title

• B32B15/20

  comprising aluminium or copper {(B32B15/016 and B32B15/017 take precedence)} · CPC title