Process and apparatus for fabricating precise microstructures and polymeric molds for making same
There is disclosed a method and apparatus for producing a polymeric film that accurately replicates a complex mold surface at least a portion of which surface has microstructured or nano-structured dimensions. A polymeric powder is electrodeposited on an underlying mold surface. Then the powder is cured to create a polymeric film. Finally the film is removed from the mold surface.
1. A rigid article comprising at least one surface with a microstructured or nanostructured pattern on at least a portion of said surface, said article comprising a first flexible polymeric layer having first and second opposing surfaces, said pattern being formed on said first surface thereof, and a second rigid polymeric layer more rigid than said first layer, said second layer being integrally bonded to said second surface of said first layer with no bonding agent therebetween to form a unitary article more rigid than said first layer.
2. The article of claim 1 wherein said first polymeric layer and said second polymeric layer are formed of different polymers.
3. The article of claim 2 wherein one of said first and second polymeric layers is formed of a thermoset polymer, and the other of said first and second layers is formed of a thermoplastic polymer.
4. The article of claim 1 wherein said first polymeric layer has a thickness of about 100-250 microns.
5. The article of claim 1 wherein said structures of said microstructured or nanostructured pattern are up to about 64 microns tall.
6. The article of claim 1 wherein said second polymeric layer has a thickness of about 9 mm.
7. The article of claim 1 wherein at least a portion of said pattern is retroreflective.
8. The article of claim 1 wherein at least a portion of said pattern comprises a Fresnel lens.
9. The article of claim 1 wherein said first layer is formed from a polymer selected from the group consisting of polycarbonate, polyesters, acrylics, urethanes, nylons, polypropylenes, polyethylenes, polyvinylchlorides and silicones.
10. The article of claim 1 wherein said first layer is formed of a thermoset polymer.
11. The article of claim 10 wherein said first layer is formed from a polymer selected from the group consisting of epoxies and epoxy-polyesters.