Appeal No. 1997-3649 Page 2
Application No. 08/432,450
BACKGROUND
Appellant's invention relates to a photosensitive element. At a simplified level, the
photosensitive element comprises a support, a layer of a photopolymerizable material on the support,
and an infrared ablation layer in direct contact with the photopolymerizable layer. The photosensitive
element is used to form a photopolymer printing plate. In order to make the printing plate, the infrared
ablation layer is laser ablated to remove selected portions of that layer from above the
photopolymerizable layer creating a mask. Upon exposure to actinic radiation, the unmasked
photopolymerizable material polymerizes while the masked portions remain unpolymerized. Treatment
with a suitable solvent removes the mask and the unpolymerized portions of the photopolymerizable
layer below the mask leaving a printing relief of photopolymerized material on the support which can be
used for flexographic printing. See the specification at page 1 and page 22. Claim 1 is illustrative of the
photosensitive element:
1. A photosensitive element for use as a photopolymer printing plate
comprising:
(a) a support;
(b) at least one layer of a photopolymerizable material on the support,
the photopolymerizable material comprising at least one elastomeric binder, at
least one monomer, at least one initiator having sensitivity to non-infrared actinic
radiation, and optionally at least one plasticizer, wherein at least one of the
monomer and the optional plasticizer is a low molecular weight material having
a weight average molecular weight of 30,000 or less; and
(c) at least one infrared ablation layer which is ablatable by infrared
radiation and opaque to non-infrared actinic radiation and wherein the infrared
ablation layer is in direct contact with the at least one photopolymerizable layer
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 Next
Last modified: November 3, 2007