ASSEMBLY OF ELEMENTS FOR FLEXOGRAPHY
An assembly can be used to provide flexographic printing plates. This assembly has (a) a flexographic photosensitive element consisting essentially of: a backing film, and a water-soluble or water-dispersible photosensitive layer comprising a photosensitive resin composition and having a front imaging surface and a backside imaging surface that is in contact with the backing film; and (b) a mask element directly in contact with the front imaging surface of the water-soluble or water-dispersible photosensitive layer. The water-soluble or water-dispersible photosensitive layer has a controlled release of at least 5 g/cm and up to and including 700 g/cm as established by ASTM D-3330 Method D, between the front imaging surface and the mask element.
1 . An assembly comprising:
(a) a flexographic photosensitive element consisting essentially of:
a backing film, and
a water-soluble or water-dispersible photosensitive layer comprising a photosensitive resin composition and having a front imaging surface and a backside imaging surface that is in contact with the backing film; and
(b) a mask element directly in contact with the front imaging surface of the water-soluble or water-dispersible photosensitive layer;
wherein the water-soluble or water-dispersible photosensitive layer has a controlled release of at least 5 g/cm and up to and including 700 g/cm as established by ASTM D-3330 Method D, between the front imaging surface and the mask element.
2 . The assembly of claim 1 , wherein the mask element is a non-silver halide, thermally-sensitive film.
3 . The assembly of claim 1 , wherein the mask element comprises one or more infrared radiation absorbing compounds, all dispersed within a polymeric binder that comprises one or more of a polyurethane, poly(vinyl butyral), (meth)acrylamide polymer, nitrocellulose, a poly(cyanoacrylate), polyacetal, or a polymer derived at least in part from any of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, and isobutyl methacrylate.
4 . The assembly of claim 1 , wherein the water-soluble or water-dispersible photosensitive layer has a controlled release of at least 30 g/cm and up to and including 200 g/cm as established by ASTM D-3330 Method D, between the front imaging surface and the mask element.
5 . The assembly of claim 1 , wherein the water-soluble or water-dispersible photosensitive layer has a controlled release of at least 40 g/cm and up to and including 110 g/cm as established by ASTM D-3330 Method D, between the front imaging surface and the mask element.
6 . The assembly of claim 1 , further comprising a release layer disposed between the backing film and the water-soluble or water-dispersible photosensitive layer.
7 . The assembly of claim 6 , wherein the release layer comprises polyvinyl alcohol, a cellulosic polymer, poly(vinyl butyral), or a hydrolyzed styrene maleic anhydride copolymer.
8 . The assembly of claim 1 , further comprising a barrier layer disposed between the backing film and the water-soluble or water-dispersible photosensitive layer.
9 . The assembly of claim 8 , wherein the barrier layer comprises poly(cyano alkyl acrylate) or a nitrocellulose, and an infrared radiation absorber.
10 . The assembly of claim 1 , wherein the mask element further comprises an ultraviolet absorber or a colorant, or both.
11 . The assembly of claim 1 , wherein the water-soluble or water-dispersible photosensitive layer comprise a UV-curable material.
12 . The assembly of claim 1 , wherein an adhesive layer is disposed between the backside imaging surface and the backing film.
13 . The assembly of claim 12 , wherein the adhesive layer comprises an ultraviolet (UV) radiation absorber.
14 . The assembly of claim 1 , wherein the backing film comprises an ultraviolet (UV) radiation absorber.
15 . The assembly of claim 1 , wherein the water-soluble or water-dispersible photosensitive layer comprises an elastomeric binder, at least one photopolymerizable monomer, and a photoinitiator that is sensitive to ultraviolet (UV) radiation.