Metallized retroreflective sheeting with increased daytime brightness
View Patent ↗A retroreflective sheeting ( 10 ) comprising a cube layer ( 20 ) having a front light-receiving surface ( 30 ) and a rear retroreflecting surface ( 32 ), and a metallic layer ( 22 ) covering the rear retroreflecting surface ( 32 ). The rear surface ( 32 ) comprises an array of retroreflective elements ( 34 ) and diffusing patches ( 36 ) within such array (without retroreflective elements ( 34 )). The metallic layer ( 22 ) covers the retroreflective elements ( 34 ) and the diffusing patches ( 36 ), whereby diffusing patches ( 36 ) scatter incoming light increasing daytime brightness to a desired level.
1. A method of making the retroreflective sheeting ( 10 ) comprising the steps of:
embossing a thermoplastic film ( 60 ) with a tool plate ( 62 );
cooling the embossed thermoplastic film ( 60 ); and
wherein the tool plate ( 62 ) has a topography corresponding to the inverse of reflective elements ( 34 ) and the diffusing patches ( 36 ); and
wherein the diffusing patches do not contain any retroreflective elements.
2. The method as set forth in claim 1 , further comprising the step of applying the metallic layer ( 22 ).
3. The method as set forth in claim 2 , wherein the metallic layer can be a metalized film, granular particles or other metallic material.
4. The method as set forth in claim 1 , including a further step of applying an adhesive layer after the step of cooling.
5. The method as set forth in claim 1 , wherein the diffusing patches are created by abrading, texturing, blunting or obliterating the retroreflective elements.
6. The method as set forth in claim 1 , wherein the retroreflective elements are cube corner elements.
7. The method as set forth in claim 6 , wherein the cube corner elements can be triangular, hexagonal or rectangular.
8. The method as set forth in claim 6 , wherein the cube corner elements are microcubes having a size of about 1 mm 2 or less.
9. The method of claim 1 , wherein each of the diffusing patches has a coverage area greater than an occupation area of a plurality of retroreflective elements.
10. The method of claim 9 , wherein the occupation area is equal to at least two retroreflective elements.
11. The method of claim 9 , wherein the occupation area is equal to at least ten retroreflective elements.
12. The method of claim 1 , including a further step of applying a UV resistant layer prior to the step of embossing.
13. The method of claim 12 , wherein the UV resistant layer and the thermoplastic film are embossed together.