Abstract:
A photosensitive printing blank having is described. The photosensitive printing blank comprises at least one photocurable layer that is capable of being selectively crosslinked and cured upon exposure to actinic radiation at a desired wavelength region comprising (a) at least one elastomeric binder, (b) at least one ethylenically unsaturated monomer, (c) a photoinitiator having a favorable absorption profile in the desired wavelength region used for exposing the at least one photocurable layer to actinic radiation, and (d) a dye, wherein the dye exhibits a suitable percent transmission as measured with a UV spectrophotometer at the desired wavelength region used for exposing the at least one photocurable layer to actinic radiation, and optionally an infrared ablatable layer disposed on the at least one photocurable layer. A method of making a relief image printing element from the photosensitive printing blank is also described.
Abstract:
A clean running flexographic relief image printing element and a method of making the same is described. The relief image printing element comprises (a) a backing layer; (b) a floor layer disposed on the backing layer and comprising a photopolymer containing a silicone monomer or silicone oil, wherein the cured floor layer has a surface energy of between about 18 to about 25 dynes/cm; (c) a cap layer disposed on the floor layer and comprising a photocurable composition that is capable of being imagewise exposed to actinic radiation to create a relief image therein, wherein the cap layer has a surface energy of between about 30 and about 40 dynes/cm; and (d) a removable cover sheet. The differential of surface energies between the floor layer and the cap layer increases how clean the plate will print over time.
Abstract:
A method of flood exposing a photocurable printing blank to actinic radiation from a UV LED light source, wherein a high intensity UV LED light source is modulated to a lower intensity. The method includes the steps of: (a) positioning the photocurable printing blank in an exposure unit, wherein the exposure unit comprises one or more high intensity UV LED light sources; (b) modulating intensity of the one or more high intensity UV LED light sources to a lower intensity; and (c) flood exposing the photocurable printing blank through the photographic negative or the digitally imaged mask layer to actinic radiation from the one or more modulated UV LED light sources.
Abstract:
Photosensitive printing blank comprises a backing layer, at least one photocurable layer disposed on the backing layer, and a laser ablatable mask layer disposed on the at least one photocurable layer, wherein the laser ablatable mask layer is laser ablated to create an in situ negative in the laser ablatable mask layer, The exposing apparatus comprises: (a) a laminating apparatus for laminating an oxygen barrier layer to a top of the laser ablated mask layer; (b) a conveyor for conveying the photosensitive printing blank through the exposing apparatus; (c) a first exposing device for exposing the at least one photocurable layer to actinic radiation from the first exposing device through the laser ablated mask layer to selectively crosslink and cure portions of the at least one photocurable layer not covered by the mask layer, and (d) a second exposing device for exposing the at least one photocurable layer to actinic radiation.
Abstract:
A method of tailoring the shape of a plurality of relief printing dots created in a photosensitive printing blank during a platemaking process is provided. The photocurable layer is exposed to actinic radiation using an array of UV LED light assemblies and the use of the array of UV LED light assemblies produces relief printing dots having at least one geometric characteristic selected from the group consisting of a desired planarity of a top surface of the relief printing dots, a desired shoulder angle of the relief printing dots and a desired edge sharpness of the relief printing dots.
Abstract:
A method of processing a flexographic printing blank to produce a relief image printing element capable of printing cleanly. The method comprises the steps of: (a) providing a flexographic printing blank comprising: (i) a support layer; (ii) at least one photocurable layer disposed on the support layer, and (iii) a laser ablatable mask layer disposed on the at least one photocurable layer. The at least one photocurable layer comprises a photocurable composition comprising: (1) at least one ethylenically unsaturated monomer; (2) at least one silicone monomer or oligomer; (3) at least one binder or oligomer; and (4) a photoinitiator. The laser ablatable mask layer is laser ablated to create an in situ negative in the laser ablatable mask layer. Thereafter, a barrier layer is disposed on the laser ablatable mask layer. The at least one photocurable layer is exposed to actinic radiation through the barrier layer and the laser ablatable mask layer.
Abstract:
A method of controlling surface roughness of a flexographic printing element during thermal processing is provided. An imaged and exposed relief image printing element is thermally developed to remove the portions of at least one layer of photopoiymer that are not crosslinked and cured by a) heating the at least one layer of photopoiymer to a sufficient temperature to soften uncured portions of the at least one layer of photopoiymer; b) causing contact between the at least one layer of photopoiymer and a blotting material, wherein when the blotting material contacts the at least one layer of photopoiymer, the softened uncured photopoiymer portions of the at least one layer of photopoiymer are absorbed into the blotting material; and c) separating the blotting material from the at least one layer of photopoiymer. Thereafter, a smooth material is inserted between the surface of the at least one layer of photopoiymer and the blotting material, in the alternative, after the flexographic printing element is removed from the thermal processor, a polymeric film is laminated onto the relief image printing element using heat and pressure. Based thereon, the average surface roughness of the relief surface of the- flexographic printing element can be reduced.
Abstract:
A method of preparing a photosensitive printing blank, the method comprising the steps of: a) coating a slip film onto a coversheet and drying the slip film; and depositing at least one layer of photosensitive material on top of the slip film coated coversheet and laminating a substrate layer to the exposed surface of the photosensitive material. The slip film comprises: i) a polymer selected from the group consisting of polystyrene and polyvinylpyrrolidone; ii) optionally, an additive. The slip film at least substantially eliminates the formation of hot spots during an analog plate making process.