Cube corner cavity based retroreflectors with transparent fill material

Abstract

Retroreflective sheeting includes a body layer having a structured surface with recessed faces forming cube corner cavities. A reflective film is disposed at least on the recessed faces, and a fill material fills the cube corner cavities. The fill material comprises radiation-curable materials, adhesives, or both, and preferably transparent radiation-curable pressure-sensitive adhesives. The fill material preferably forms a continuous layer covering both the recessed faces and upper portions of the structured surface. A transparent cover layer preferably contacts the fill material layer.

1 - 34 . (canceled)  
   
   
       35 . A method of making a cube corner article, comprising: 
 providing a body layer having a structured surface that includes recessed faces defining cube corner cavities;    applying a film of reflective material to the recessed faces;    applying to the structured surface a radiation-curable composition suitable for bonding to the film of reflective material; and    exposing the composition to radiation sufficient to crosslink the composition after the composition has filled the cube corner cavities.    wherein the body layer has an elastic modulus that is greater than about 690 MPa and the radiation-cured, cross-linked composition has an elastic modulus that is less than about 690 MPa.    
   
   
       36 . The method of claim  1 , wherein the radiation-cured, cross-linked composition has an elastic modulus that is less than about 345 MPa.  
   
   
       37 . The method of claim  1 , wherein the second applying step applies the composition at a thickness sufficient to form a composition layer covering the recessed faces.  
   
   
       38 . The method of claim  1 , further comprising: 
 providing a first cover layer; and    laminating the first cover layer to the article.    
   
   
       39 . The method of claim  4 , wherein the first cover layer has the flowable composition applied thereto, and the second applying step is carried out by the laminating step.  
   
   
       40 . The method of claim  4 , wherein the first cover layer comprises a release liner that does not bond to the composition.  
   
   
       41 . The method of claim  6 , further comprising: 
 removing the release liner;    providing a second cover layer suitable for bonding to the composition; and    laminating the second cover layer to the composition.    
   
   
       42 . The method of claim  1 , wherein the second applying step is carried out such that the flowable composition incompletely fills the cube corner cavities.  
   
   
       43 . The method of claim  8 , further comprising: 
 providing a cover layer; and    laminating the cover layer to the article before the flowable composition has filled the cube corner cavities.    
   
   
       44 . The method of claim  1 , wherein the flowable composition is at least 95% polymerized during the second applying step.  
   
   
       45 . The method of claim  1 , wherein the structured surface further includes a top surface separating the cube corner cavities.