Aluminum-Coated Glass Microspheres, also called retroreflective microspheres, half-shell coated spheres or hemispherically coated spheres, have a half-shell aluminum coating applied to solid barium titanate glass microspheres. The spheres are hemispherically
coated with a thin aluminum shell to produce a bright retroreflective response directed back to the light
source and to the observer. The light bounces off the
aluminum-coated half of the sphere produces the retro reflective effect
that provides the desired high visibility in dark conditions.
Retroreflective microspheres can be used with all binders — water or solvent-borne paints, epoxy, thermoplastic, vinyl, polyester, PMMA, polyurethane, polyurea or powder coatings. Reflective coatings are easily applied to virtually any solid surface including metals, plastic or concrete using most application methods. Glass microspheres will not shatter or shear when used in most high speed spray guns, extruders or powder coating chambers.
P2453BTA microspheres are made of barium
titanate glass hemispherically coated with aluminum. Barium titanate glass has a higher Refractive Index [RI]
than soda lime glass: 1.9 compared to 1.5. The Refractive Index of a
material measures the degree a ray of light bends when it moves from one
medium to another. Its practical significance is that it indicates how
light will reflect back to the viewer. Barium titanate glass with its
higher RI will reflect back more directly to the viewer than soda lime
glass, which will scatter to some degree. This direct reflection is
particularly important for applications when retro reflectivity is
desired such as guard rails, traffic signs or reflective tape or