Photopolymer
A photopolymer is a polymer that changes its properties when exposed to light, often in the ultraviolet frequency of the electromagnetic spectrum. These polymers are used as image carriers in flexographic printing, as components of fillings for dentistry, as ADA-compliant architectural signage, and in rapid prototyping for the stereolithography and 3D printing processes. The basic material is soft and light sensitive, and when produced will undergo a selective exposure, development and curing process. Some commercial manufacturers for photopolymer include DuPont Cyrel, Flint Nyloflex, MacDermid, Asahi Photoproducts, Eastman-Kodak, Novacryl, Elaslon, and Soleflex Exaprint.
Process
- exposing imagewise a photopolymerizable element to actinic radiation emitting a wavelength in the range of 365 nm.
- removing the unexposed or unpolymerized areas of the plate, generally through the use of a solvent.
- drying the resulting plate.
The photopolymerized element can then be detackified by exposing the element to ultraviolet radiation emitting a wavelength in the range of 254 nm. To ensure final plate hardening and photopolymerization, the printing element can be further post-exposed to radiation emitting at wavelengths in the range of 365 nm.
Current platemaking processes utilize various sources of radiation for developing relief images and maximizing plate hardening. For example, actinic radiation from a variety of sources can be used, including commercial ultraviolet fluorescent tubes, medium, high, and low pressure mercury vapor lamps, argon glow lamps, photographic flood lamps, pulsed xenon lamps, carbon arc lamps, light-emitting diodes, etc.