Infrared reflecting cube-cornered sheeting

• US 5,200,851 A
• Filed: 02/13/1992
• Issued: 04/06/1993
• Est. Priority Date: 02/13/1992
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Burns, David M., Coderre, James C.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/835,619
• Time in Patent Office: 418 Days
• Field of Search: 359/350, 359/351, 359/529, 359/530, 359/531, 359/532, 359/533, 252/587
• US Class Current: 359/351
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet
• CPC Class Codes: G02B 5/22 Absorbing filters G02B5/201 - G02B5/208 take precedence

Abstract

Cube-corner type retroreflective articles which retroreflect infrared light but do not substantially retroreflect visible light. The cube-corner elements comprise a polymeric matrix selected to be highly transmissive to infrared light but substantially opaque to visible light.

Claims

1. A retroreflective article having first and second major sides, said first side being substantially flat and said second side having an array of cube-corner retroreflective elements thereon, wherein said elements comprise a polymeric matrix which is transmissive to infrared light but which is substantially opaque to visible light.

2. The article of claim 1 wherein said matrix absorbs at least about 90 percent of all wavelengths of light from about 400 millimicrons to about 700 millimicrons.

3. The article of claim 1 wherein said matrix absorbs at least about 99 percent of all wavelengths of light from about 400 millimicrons to about 700 millimicrons.

4. The article of claim 1 wherein said matrix absorbs at least about 99.5 percent of all wavelengths of light from about 400 millimicrons to about 700 millimicrons.

5. The article of claim 1 wherein said matrix transmits at least about 25 percent of all wavelengths of light from about 750 millimicrons to about 1100 millimicrons.

6. The article of claim 1 wherein said matrix transmits at least about 50 percent of all wavelengths of light from about 750 millimicrons to about 1100 millimicrons.

7. The article of claim 1 wherein said matrix transmits at least about 90 percent of all wavelengths of light from about 750 millimicrons to about 1100 millimicrons.

8. The article of claim 1 wherein said matrix transmits at least about 95 percent of all wavelengths of light from about 750 millimicrons to about 1100 millimicrons.

10. The article of claim 1 wherein said matrix absorbs at least about 99.5 percent of all wavelengths of light between about 380 millimicrons and about 750 millimicrons.

11. The article of claim 1 wherein said matrix comprises a polymer which is substantially transmissive of both infrared light and visible light and a colorant which is transmissive to infrared light but which is substantially opaque to visible light.

12. The article of claim 1 wherein the absorbance of visible light by said matrix is such that substantially all visible light is absorbed within said article'"'"'s minimum pathlength.

13. The article of claim 1 wherein said polymer is selected from the group consisting of:

polycarbonate, polyalkylacrylates, polyalkylmethacrylates, polyesters, vinyl polymers, polyurethanes, cellulose esters, fluoropolymers, polyolefins, ionomeric copolymers, and copolymers of ethylene or propylene with acrylic acid, methacrylic acid, and vinyl acetate.

14. The article of claim 1 wherein said colorant is a dye selected from the group consisting of:

C.I. Solvent Violet 13, C.I. Solvent Violet 31, C.I. Solvent Violet 32, C.I. Solvent Violet 33, C.I. Solvent Violet 36;

C.I. Solvent Blue 94, C.I. Solvent Blue 97, C.I. Solvent Blue 101, C.I. Solvent Blue 121, C.I. Disperse Blue 60, C.I. Disperse Blue 198;

C.I. Solvent Green 3, C.I. Solvent Green 26, C.I. Solvent Green 28;

C.I. Solvent Yellow 93, C.I. Solvent Yellow 112, C.I. Solvent 113, C.I. Solvent 128, C.I. Solvent 129, C.I. Solvent 130, C.I. Solvent 163, C.I. Disperse Yellow 54, C.I. Disperse Yellow 64, C.I. Disperse Yellow 160;

C.I. Solvent Orange 60, C.I. Solvent Orange 68;

C.I. Solvent Orange 72;

C.I. Solvent Orange 86, C.I. Disperse Orange 47;

C.I. Solvent Red 52, C.I. Solvent Red 111, C.I. Solvent Red 117, C.I. Solvent Red 135, C.I. Solvent Red 138, C.I. Solvent Red 139, C.I. Solvent Red 169, C.I. Solvent Red 195, C.I. Solvent Red 207, and C.I. Disperse Red 5, Amaplast Violet PK, and mixtures thereof.

15. The article of claim 1 wherein said colorant comprises one or more pigments selected from the group consisting of:

LITHOSOL™

Fost Scarlet, Benzedine Yellow, HELIOGEN™

Blue, C.I. Pigment Green 7, C.I. Pigment Blue 15, C.I. Pigment Red 167, and C.I. Pigment Yellow 89.

9. The article of claim i wherein said matrix absorbs at least about 90 percent of all wavelengths of light from about 400 millimicrons to about 700 millimicrons and transmits at least about 25 percent of all wavelengths of light from about 750 millimicrons and about 1150 microns.