Retroreflective article comprising multiple locally-laminated layers

Patent metadata

Field	Value
Publication number	US-12228755-B2
Application number	US-202017605654-A
Country	US
Kind code	B2
Filing date	Apr 24, 2020
Priority date	Apr 25, 2019
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

A retroreflective article comprises a binder layer and a plurality of retroreflective elements, each retroreflective element comprising a transparent microsphere partially embedded in the binder layer. At least some of the retroreflective elements comprise a first locally laminated layer and a second locally laminated layer that may be reflective layers. A transfer article comprises a disposable carrier layer in which the retroreflective article is detachably disposed with at least some of the transparent microspheres in contact with the disposable carrier layer.

First claim

What is claimed is:

1. A retroreflective article comprising:
a binder layer; and,
a plurality of retroreflective elements spaced over a length and breadth of a front side of the binder layer, each retroreflective element comprising a transparent microsphere partially embedded in the binder layer so as to exhibit an embedded area of the transparent microsphere;
wherein at least some of the retroreflective elements each comprise a first locally-laminated layer that is embedded between the transparent microsphere and the binder layer; and, a second locally-laminated layer that is embedded between the transparent microsphere and the binder layer;
the first and second locally-laminated reflective layers being in the form of discontinuous, discrete reflective layers that exhibit one or more edges indicating that the reflective layer was locally broken off from a layer of reflective material that previously laterally surrounded the reflective layer, with at least some of the first and second locally-laminated reflective layers exhibiting discontinuities in the form of cracks, gaps or fracture lines;
wherein for at least some of the microspheres on which the first and second locally-laminated, embedded layers are present, at least a portion of the second locally-laminated, embedded layer is positioned in parallel to the first locally-laminated, embedded layer so that incoming light rays can reach the in-parallel portion of the second locally-laminated, embedded layer without having to pass through any portion of the first locally-laminated, embedded layer.

2. The retroreflective article of claim 1 wherein the first locally-laminated, embedded layer and/or the second locally-laminated, embedded layer is a reflective layer.

3. The retroreflective article of claim 2 wherein the first locally-laminated, embedded layer is a first reflective layer and wherein the second locally-laminated, embedded layer is a second reflective layer.

4. The retroreflective article of claim 3 wherein at least 50 percent of the retroreflective elements of the retroreflective article each comprise a first locally-laminated, embedded reflective layer and/or a second locally-laminated, embedded reflective layer.

5. The retroreflective article of claim 3 wherein at least some of the first locally-laminated, embedded reflective layers are localized layers and at least some of the second locally-laminated, embedded reflective layers are localized layers.

6. The retroreflective article of claim 1 wherein for at least some of the microspheres on which the first and second locally-laminated, embedded layers are present, at least a portion of the second locally-laminated, embedded reflective is positioned rearward of, and in series with, the first locally-laminated, embedded layer, so that incoming light rays have to pass through the first locally-laminated, embedded layer to reach the in-series portion of the second locally-laminated, embedded layer.

7. The retroreflective article of claim 1 wherein for microspheres on which the first and second locally-laminated, embedded layers are present, the first and second locally-laminated, embedded layers each occupy an angular arc of at most 180 degrees.

8. The retroreflective article of claim 1 wherein for at least some of the microspheres on which the first and second locally-laminated, embedded layers are present, the first locally-laminated, embedded layer occupies an angular arc of less than 40 degrees and the second locally-laminated, embedded layer occupies an angular arc of greater than 60 degrees.

9. The retroreflective article of claim 1 wherein at least some of the locally-laminated, embedded layers each comprise a selective-bonding layer that has first and second major surfaces that exhibit differential bonding from each other.

10. The retroreflective article of claim 1 wherein at least some of the locally-laminated, embedded layers each comprise an embrittlement layer.

11. The retroreflective article of claim 1 wherein at least some of the locally-laminated, embedded layers are reflective layers that each comprise a metal reflecting layer.

12. The retroreflective article of claim 1 wherein at least some of the locally-laminated, embedded layers are wavelength-selective reflective layers that exhibit a predetermined wavelength of peak reflection.

13. The retroreflective article of claim 1 wherein the first locally-laminated, embedded layers are first reflective layers that each comprise a metal reflecting layer, and wherein the second locally-laminated, embedded layers are wavelength-selective reflective layers that exhibit a predetermined wavelength of peak reflection.

14. The retroreflective article of claim 1 wherein the first locally-laminated, embedded layers are first wavelength-selective reflective layers that exhibit a first predetermined wavelength of peak reflection; and, wherein the second locally-laminated, embedded layers are second wavelength-selective reflective layers that exhibit a second predetermined wavelength of peak reflection and wherein the second predetermined wavelength of peak reflection differs from the first predetermined wavelength of peak reflection by at least 50 nm.

15. The retroreflective article of claim 1 wherein at least the second locally-laminated, embedded layers are reflective layers, and wherein the first locally-laminated, embedded layers and the second locally-laminated, embedded reflective layers are configured so that at least at one wavelength between 400 nm and 700 nm, the retroreflective article exhibits a percent retroreflectance at a 30 degree entrance angle, that is greater than a percent reflectance exhibited at a 5 degree entrance angle, by at least 2 percent.

16. The retroreflective article of claim 1 wherein at least some of the retroreflective elements comprise an intervening layer at least a portion of which is disposed between the transparent microsphere and the binder layer so that the first locally-laminated, embedded layer, and the second locally-laminated, embedded layer, are positioned rearward of the intervening layer, between the intervening layer and the binder layer.

17. The retroreflective article of claim 1 wherein the binder layer comprises a colorant.

18. A transfer article comprising the retroreflective article of claim 1 and a disposable carrier layer on which the retroreflective article is detachably disposed with at least some of the transparent microspheres in contact with the disposable carrier layer.

19. A substrate comprising the retroreflective article of claim 1 , wherein the binder layer of the retroreflective article is coupled to the substrate with at least some of the retroreflective elements of the retroreflective article facing away from the substrate.

20. A retroreflective article comprising:
a binder layer; and,
a plurality of retroreflective elements spaced over a length and breadth of a front side of the binder layer, each retroreflective element comprising a transparent microsphere partially embedded in the binder layer so as to exhibit an embedded area of the transparent microsphere;
wherein at least some of the retroreflective elements each comprise a first locally-laminated layer that is embedded between the transparent microsphere and the binder layer; and, a second locally-laminated layer that is embedded between the transparent microsphere and the binder layer;
the first and second locally-laminated reflective layers being in the form of discontinuous, discrete reflective layers that exhibit one or

Assignees

• 3M Innovative Properties Company

Inventors

• Gotrik Kevin W
• Chen-Ho Kui
• Clarke Graham M
• Jones Scott J
• Mccoy Michael A
• Niwas Shri
• Rowe David J
• Whiting Tien Yi T H
• Xia Ying

Classifications

• B32B37/18

  involving the assembly of discrete sheets or panels only · CPC title

• B32B37/144

  using layers with different mechanical or chemical conditions or properties, e.g. layers with different thermal shrinkage, layers under tension during bonding (constructional features for tensioning B32B38/1825) · CPC title

• B32B37/1292

  selectively, e.g. in stripes, in patterns (B32B37/0076 takes precedence) · CPC title

• B32B37/025

  Transfer laminating · CPC title

• B32B37/0084

  Point bonding · CPC title