Abstract:
The use of biodegradable polymer films in the manufacture of photosensitive relief image printing plates is described, including printing plates produced from liquid photopolymer resins and from sheet polymers as well as direct write/laser engravable printing plates. The biodegradable polymer films can be used as substrate layers, oxygen barrier layers, and coverfilms and, once the printing plates have been used and disposed of, the biodegradable polymer films are capable of decomposing in the environment
Abstract:
Thermally developing a photocurable printing blank to produce a relief pattern comprising a plurality of relief dots. The photocurable printing blank comprises a backing layer having at least one photocurable layer disposed thereon and a laser ablatable mask layer disposed on top of the at least one photocurable layer. The method includes: (1 ) imaging a photo curable layer by ablating the mask layer to create the relief pattern; (2) laminating an oxygen barrier membrane atop the ablated mask layer; (3) exposing the printing blank to actinic radiation through the oxygen barrier membrane and ablated mask layer to selectively crosslink and cure portions of the photocurable layer, thereby creating the relief pattern; (4) removing the oxygen barrier membrane from atop the ablated mask layer; and (5) thermally developing the printing blank to remove the ablated mask layer and uncured portions of the photo curable layer and reveal the relief pattern.
Abstract:
Various methods for providing multi-layer compressible foam sheets for backing relief image printing elements are described. The use of multi-layer compressible foam sheets as backing layers allows for customization of the compressible layer, for example to impact the print result, maximize cushion life, enhance press speed characteristics and to modify the imaging of the printing plate resin. As a result, a customized compressible foam sheet can be used for backing various relief image printing plates to achieve a desired result.
Abstract:
A method of tailoring the shape of a plurality of relief dots created in a photosensitive printing blank during a digital platemaking process is provided. The photosensitive printing blank comprises a laser ablatable mask layer disposed on at least one phoiocisrahle layer which is mountab!e on a printing sleeve. The method comprises the steps of (1) placing a barrier layer on top of the laser ablatable mask layer; (2) laser ablating the laser ablatable mask layer to create an in situ negative in the laser ablatable layer; (3) exposing the at least one photocurable layer to actinic radiation through the in situ negative; (4) removing the barrier layer; and (5) developing the imaged and exposed photosensitive printing blank to reveal the relief image therein, the relief image comprising the plurality of relief dots. The presence of the barrier layer produces printing dots having desired geometric characteristics.
Abstract:
A method of controlling surface roughness of a flexographic printing element during thermal processing is provided. The relief image printing element of the invention comprises a photopolymer that has been selectively imagewise exposed to actinic radiation to selectively crosslink and cure portions of the photopolymer. The method generally comprises removing uncrosslinked and uncured portions of the photopolymer by heating the photopolymer and contacting it with a blotting material. The photopolymer is then contacted under heat and pressure with a smooth material, e.g., a laminated polymeric film, which smooth material is removed resulting in a relief image printing element with reduced surface roughness.
Abstract:
A method of tailoring the shape of a plurality of relief dots created in a photosensitive printing blank during a digital platemaking process is provided. The photosensitive printing blank comprises a laser ablatable mask layer disposed on at least one phoiocisrahle layer which is mountab!e on a printing sleeve. The method comprises the steps of (1) placing a barrier layer on top of the laser ablatable mask layer; (2) laser ablating the laser ablatable mask layer to create an in situ negative in the laser ablatable layer; (3) exposing the at least one photocurable layer to actinic radiation through the in situ negative; (4) removing the barrier layer; and (5) developing the imaged and exposed photosensitive printing blank to reveal the relief image therein, the relief image comprising the plurality of relief dots. The presence of the barrier layer produces printing dots having desired geometric characteristics.
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 photocurable printing blank comprises a backing layer having a photocurable layer disposed thereon, a barrier layer disposed on the photocurable layer, and a laser ablatable mask layer disposed on top of the barrier layer. The method includes the steps of (1 ) imaging the at least one photo curable layer by ablating the laser ablatable mask layer to create the relief pattern on the photocurable printing blank; (2) exposing the printing blank to actinic radiation through the barrier layer and mask layer to selectively crosslink portions of the photocurable layer, thereby creating the relief pattern; (3) developing the printing blank to remove the barrier layer, the laser ablated mask layer and uncured portions of the photo curable layer and reveal the relief pattern. The method can also be used with an analog platemaking process that uses a negative instead of an ablatable mask layer.