RETRO REFLECTIVE APPLICATIONS

PRIZMALITE AND ENHANCED VISIBILITY

Prizmalite has developed proprietary coatings that expand the effectiveness of its glass microspheres to enhance visibility in:

  • DECORATIVE AND SAFETY INKS
  • ROAD LINING AND GUARD RAIL PAINTS
  • RETRO REFLECTIVE POWDER COATINGS

Prizmalite’s proprietary coatings position its coated microspheres at the surface of either water (silane coatings) or solvent-based (fluorochemical coatings) paints or formulations. This placement maximizes the transmission of light through the bead and the light’s “bounce back” to create enhanced retro reflectivity.

RETRO REFLECTIVITY IN TECHNO COLOR

Prizmalite has also developed proprietary coatings and application methods to adhere dyes and pigments to glass spheres. Pigmented coatings allow expanded applications for hemispherically aluminum coated sphere in particular. Whereas previously their grey color limited the use of metallized spheres to only dark resin systems, Prizmalite’s pigmented coatings now allow these spheres to be added to most colored paints or plastics—even yellow—with only a slight decrease in the retro reflectivity of the colored sphere, assuring formulations that are attractive by day and brightly visible at night.

WHAT IS REFLECTIVITY? HOW DOES IT WORK?

Glass beads greater than 100 microns in diameter have long been used to enhance visibility in road lining paints. For the first time, Prizmalite’s specially-coated glass spheres can create a range of optical effects: from daytime brilliance to night-time reflectivity.

Almost all surfaces reflect some light. Night time visibility depends on an object’s retro reflectivity—the direct return of light straight back to the light source with a minimum scattering of light. The greater the retro reflectivity, the stronger the visibility of objects in dark or night time conditions.

Currently, two basic methods are used to produce retro-reflective materials: the prismatic cube corner method and hemispherically aluminum-coated barium titanate glass beads. The prismatic cube corner method is based on triangular pyramid shaped glass cubes that are aligned so the triangular base is directed toward a beam of light. The light passes through the pyramid base and internally “bounces” off each of the three sides of the pyramid before being directed back to the original light source. Products such as retro- reflective tapes and sheeting are based on the prismatic cube corner method—a very efficient form of retro reflection but one that is limited in terms of its viewing angles and ease of appliction.

Prizmalite’s retro reflective technology is based on hemispherically aluminum-coated barium titanate glass beads. The hemispheric aluminum coating creates the mechanism for retro-reflectivity since light passing through the clear half of the glass bead “bounces” off the reflective aluminum-coated back, directing the light back to the source.

PRIZMALITE’S BREAKTHROUGH

Prizmalite’s proprietary coatings create a tension between the microsphere and the surrounding resin that repels the sphere to the surface. This “pop up” effect positions the sphere to maximize the light transmission and enhance the retro-reflectivity.

Prizmalite’s fluorochemical and silane-based coatings can be applied to any of its glass microspheres but their application is particularly important for its metallized spheres: because of the high relative density of barium titanate glass, these spheres will typically sink in any resin system in which they are incorporated. Unless metallized spheres are at the surface of a formulation, light cannot travel through the clear hemisphere to bounce off the metallized shell and create a retro reflective effect. Metallized beads dispersed throughout a resin provide little benefit in terms of retro-reflectivity. Placement at the surface allows for a reduction in the amount of microspheres needed to achieve the desired level of retro reflectivity.

Prizmalite’s specially formulated coatings for adhering pigments or dyes to glass spheres promote truer color matching when metallized spheres, in particular, are incorporated into pigmented formulas. Colored clear spheres can be substituted for more expensive pigments and still maintain the targeted color intensity and the desired level of retro-reflectivity.