Retroreflective articles including optically active areas and optically inactive areas
This disclosure generally relates to retroreflective articles and methods of making such articles.
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 that is less than 1000 microns; and
wherein the sealing layer further 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 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.
2. The retroreflective article of claim 1 , wherein the cell size is less than 750 microns.
3. The retroreflective article of claim 1 , wherein the second region forms multiple discrete cells.
4. The retroreflective article of claim 3 , wherein the multiple discrete cells each have a cell shape and a cell size and at least one of the shape and size of at least two different discrete cells are unequal.
5. The retroreflective article of claim 3 , wherein the multiple discrete cells each have a cell shape and a cell size that are substantially equal to each other.
6. The retroreflective article of claim 1 , wherein the sealing layer is a pressure sensitive adhesive.
7. 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.
8. The retroreflective article of claim 1 , wherein the retroreflective article exhibits a coefficient of retroreflection R A that is not less than about 80 cd/(lux·m 2 ) for an observation angle of 0.2 degrees and an entrance angle of −4 degrees.
9. 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.
10. 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.
11. 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.
12. 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.
13. The retroreflective article of claim 1 , wherein less than about 65% of the structured surface is retroreflective.
14. The retroreflective article of claim 1 , wherein the second region is raised relative to the first region.
15. 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 that is less than 1000 microns; and
wherein the sealing layer further 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 multiple discrete cells each have a cell shape and a cell size and at least one of the shape and size of at least two different discrete cells are unequal.
16. 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 that is less than 1000 microns; and
wherein the sealing layer further 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 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.