Retroreflective articles including optically active areas and optically inactive areas

• US 9,618,663 B2
• Filed: 04/15/2010
• Issued: 04/11/2017
• Est. Priority Date: 04/15/2010
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Smith, Kenneth L., Free, Michael Benton, Thakkar, Bimal V., Chiu, Raymond C.
• Primary Examiner(s): Phan, James
• Application Number:
  US13/641,271
• Publication Number:
  US 20130135731A1
• Time in Patent Office: 2,553 Days
• Field of Search: 359529-542
• CPC Class Codes: B32B 15/20 comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: B32B 2250/44 Number of layers variable across the laminate
• CPC Class Codes: B32B 2255/10 on synthetic resin layer or on natural or synthetic rubber layer
• CPC Class Codes: B32B 2255/12 on paper layer
• CPC Class Codes: B32B 2255/20 Inorganic coating
• CPC Class Codes: B32B 2255/26 Polymeric coating
• CPC Class Codes: B32B 2307/416 Reflective
• CPC Class Codes: B32B 2307/418 Refractive
• CPC Class Codes: B32B 2307/732 Dimensional properties
• CPC Class Codes: B32B 2307/75 Printability
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/281 comprising polyimides
• CPC Class Codes: B32B 27/302 comprising aromatic vinyl (co)polymers, e.g. styrenic (co)polymers
• CPC Class Codes: B32B 27/306 comprising vinyl acetate or vinyl alcohol (co)polymers
• CPC Class Codes: B32B 27/308 comprising acrylic (co)polymers
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/322 comprising halogenated polyolefins, e.g. PTFE
• CPC Class Codes: B32B 27/325 comprising polycycloolefins
• CPC Class Codes: B32B 27/34 comprising polyamides
• CPC Class Codes: B32B 27/38 comprising epoxy resins
• CPC Class Codes: B32B 27/42 : comprising condensation resins of aldehydes, e.g. with phenols, ureas or melamines
• CPC Class Codes: B32B 3/263 : characterised by a layer having non-uniform thickness
• CPC Class Codes: B32B 3/30 : characterised by a layer formed with recesses or projections, e.g. hollows, grooves, protuberances, ribs apertured layer B32B3/266; layer with cavities or internal voids B32B3/26
• CPC Class Codes: B32B 7/12 : using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: G02B 5/122 : cube corner, trihedral or triple reflector type
• CPC Class Codes: G02B 5/124 : plural reflecting elements forming part of a unitary plate or sheet

Abstract

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

Claims

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·

m²) 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 m²) 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.