Photohardening

Photohardenable electrostatic master having improved backtransfer and charge decay. Blanchet-Fincher, Graciela B. Fincher, Curtis R., Jr. Cheung, Lawrence K. F Dessauer, Rolf Looney, Catharine E. (DuPont de Nemours, E. 

Method for preparing positive and negative images using photohardenable electrostatic master. Kempf, Richard J. (du Pont de Nemours, E. I., and Co.)... 

Dextrin is extensively used in the manufacture of photosensitive materials (developers, thermal recording materials, optical information recording media, and photohardenable printing and transfers). Among other uses, dextrin diminishes the absorptivity and flabbiness of diazo copying... 

Photopolymerizable layers usually consist of a polymeric binder, such as poly(methyl methacrylate) or poly(vinylbutal) a photopolymerizable monomer, such as methylene glycol bisacrylate or polyethylene glycol bismethacrylate a thermal stabilizer, />-methoxyphenol a photoinitiator, such as an alkyl anthraquinone and a dye, such as a cyanine dye. On exposure to light in an imagewise manner the exposed areas are photohardened by formation of caged-type photopolymerized, two-dimensional crosslink structures. 

Sample Preparation. Photohardenable formulations based on TMPTA in combination with other reagents including photoinitiators (Quanticure ITX or 7-diethylamino-3-cinnamoyl coumarin, depending on the specific experiment) and colorless dye precursors developable upon contact with acidic resin coated paper were used as a test composition. 

Kodama H (1981) Automatic method for fabricating a three-dimensional plastic model with photohardening polymer. Rev Sci Instrum 52 1770-1773... 

Ogawa, E., Japanese Patent Application 63-265238, Photohardening and Aqueous-Developing Dielectric Paste Composition, November 1,1988. 

U.S. 4,180 03. Photohardenable Films Having High Resolution Containing Nitroso Dimers. 

Stability of masters was not found to be an issue, as the coversheet protected the system effectively, and the recipe(s) were sufficiently close to those of the stable CROMALIN proofing film. Nevertheless effort to obtain enhanced performance were made and patents issued for a photohardenable electrostatic master containing a conductive sealant layer U.S. 4,911,911 (Legere) and a polyolefin backside coating for photosensitive reproduction element, U.S. 5,139,905 (Legere). 

U.S. 5,139,905. Photohardenable Electrostatic Master Containing a Conductive Sealant Layer. 

When a triphenylmethane leucodye was incorporated in the coating, the exposed area became colored, giving some indication of the exposure. Additionally, the photohardenable electrostatic master had improved charge decay and back transfer. 

U.S. 4,849,314. Photohardenable Electrostatie Master Containing Electron Acceptor or Donor. 

U.S. 5,043,237. Inhibitor-Containing Photohardenable Electrostatic Master Compositions Having Improved Resolution. Blanchet-Fincher, Graciela B. Chang, Catherine Teh-Lin (E. I. du Pont de Nemours and Company). August 27, 1991. Cl. 430/49 430/43 430/281.1. Appl. January 12,... 

U.S. 4,859,551. Process for Preparing Positive and Negative Images Using Photohardenable Electrostatic Master. Kempf, Richard J. (E. I. Du Pont de Nemours and Company). August 22,1989. 

Cl. 430/49 430/291 430/306 430/309. Appl. November 4, 1987. Process for producing negative or positive images from a photohardenable electrostatic master comprising an electrically conductive... 

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