Abstract:
A method and apparatus for forming "seamless" retroreflective sheeting is described. At least two mold surfaces (10, 10') are used, each having alternate areas of arrays of prism recesses and spaces. In a first step, prisms are formed in one of the mold surfaces (10) and applied to a base film (46) or web. Next, prisms are formed on the second mold (10') surface and applied to the spaced areas left in the first step.
Abstract:
A retroreflective structure and a method for forming the structure are disclosed. The structure has a window side and a facet side. The facet side has a plurality of steps with treads and risers intersecting at an angle. The risers include an array of retroreflective elements. Preferably, the elements are cube-corner prisms.
Abstract:
A durable reusable polymeric mold (10) for casting a microstructure sheet having an array of prism elements and a method for forming the microstructure sheet are disclosed. A polymeric mold has a facet side (14) and a base side (16) comprising an array of prism elements upon which a radiation cured sheet can be formed. A protective surface layer (20) can be formed on the facet side (14) of the polymeric mold (10). The protective surface layer (20) is sufficiently opaque to radiation to protect the polymeric mold (10) from damage when the curable sheet (22) is formed and is sufficiently bonded to the polymeric mold to allow the cured sheet (22) to be removed from the protective surface layer (20) while not substantially removing the protective surface layer (20) from the polymeric mold (10). The microstructure sheet can be used as a retroreflective structure.
Abstract:
Retroreflective sheet material is produced by forming sheet material with closely spaced retroreflective formations (12) on one face and depositing on this face silver and copper atoms having high kinetic energy to provide a reflective metallic deposit (14) comprising a base layer of metallic silver and an overlying layer of metallic copper. An organic protective coating (20) is thereafter applied over the reflective metallic deposit (14). Light rays passing through the front face of the body enter the retroreflective formations (12), impinge upon the interface provided by the silver base layer and are retroreflected therefrom. As a result, the sheet material exhibits a bright white appearance in daylight as well as a bright white coloration at night when an incandescent beam impinges thereon.