Durable retroreflective optical elements
AssigneePotters Industries, Inc.
InventorsGovindasamy Paramasivam Rajendran, Jeffrey Lee Stricker
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Abstract
A retroreflective optical element is provided in which modified glass beads having a high refractive index are embedded on the surface of a thermoplastic core. The glass beads are heated to a temperature near the softening point of the thermoplastic core and the heated beads and thermoplastic cores are mixed in a fluidized bed. The beads embed into the thermoplastic core and are also chemically bonded thereto through a silane coupling agent provided on the beads.
Claims16
A retroreflective optical element comprising a reactive thermoplastic core and at least one modified glass bead having a high refractive index embedded on the surface of said thermoplastic core.
A process for manufacturing optical elements comprising the steps of
- a. providing a plurality of reactive thermoplastic pellets and a plurality of modified glass beads into a fluidized bed;
- b. heating said modified glass beads to a temperature near the softening point of said thermoplastic pellets;
- c. mixing said heated beads with said thermoplastic pellets, whereby said glass beads embed within said thermoplastic pellets to form said optical elements;
- and
- d. sieving the mixture to isolate said optical elements.
Dependencies are inferred from the claim text.