Optical-Grade Thermoset

Feb. 8, 2007
CR-39TM, a thermoset monomer ADC (allyl diglycol carbonate) from Fosta-Tek Optics Inc., Leominster, Mass., can replace glass in instrument display windows.

The use of a special Fosta-Tek Optics formulation of the thermoset monomer ADC (allyl diglycol carbonate) is rapidly growing as a replacement for glass in a number of instrument display window and data-capture system applications.

As cast sheets, it combines optical quality, chemical and gamma-radiation resistance, economics, and ease of fabrication. It has a 92% transmission value, haze as low as 0.3 to 0.9%, and weighs half as much as glass. The material is sometimes referred to as organic glass because its optical properties are close to those of mineral glass.

Unlike extrusion or injection molding, thermosetting ADC generates little birefringence. Its Abbe Value of 59 is close to that of glass (60) and higher than any other optical plastic. ADC can be made into specific shapes and sizes. It can be cast in thicknesses from 0.03 to 0.25 in. and cut to sizes up to 25 in.2

Antiglare finishes are cast directly into ADC windows and antireflective thin-film coating can be applied to enhance transmission. A wide range of dyes provides peak transmission at specific nanometer ranges to make displays easy to read.

Fosta-Tek Optics Inc.,
(978) 534-6511,

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