Optical structures including polyurea
View Patent ↗Optical structures and sheeting that include polyurea and method for forming same are proposed in accordance with aspects of the present invention. One and two-component layers can be used to form the optical structures. The optical structures can include microstructures formed from polyurea. The sheeting can include at least one of cube-corner prisms, open-faced cube-corner prisms, linear prisms, lenticular lenses, moth-eye structures, lenses, Fresnel lens arrays, lenses, and fish-eye lens arrays.
1. Optical sheeting comprising microstructures that include polyurea, wherein the polyurea is formed from an isocyanate prepolymer which comprises a low aliphatic polyisocyanate resin based on hexamethylene diisocyanate (HDI) and amine resin.
2. The sheeting of claim 1 , wherein the polyurea includes a polyfunctional polyol.
3. The sheeting of claim 1 , wherein the isocyanate prepolymer includes a low viscosity solvent-free polyfunctional aliphatic polyisocyanate resin based on hexamethylene diisocyanate (HDI).
4. The sheeting of claim 1 , wherein the amine resin has an amine value of between about 100 and 300.
5. The sheeting of claim 1 , wherein the polyurea further includes a polyol.
6. The sheeting of claim 5 , wherein the polyol includes a branched polyether polyol.
7. The sheeting of claim 5 , wherein the polyol has a hydroxyl number in the range of between about 25 and 400.
8. The sheeting of claim 5 , wherein the polyol is difunctional.