Patent ID: 7718111

Claim:
A process for producing a three-dimensional article in sequential cross-sectional layers in accordance with a model of the article, the process comprising the steps of: (1) forming a first layer of a photocurable composition comprising (a) a cationically curable compound; (b) an acrylate-containing compound; (c) a hydroxyl-containing compound; (d) a cationic photoinitiator; and (e) a free radical photoinitiator wherein said composition has less than 0.54 equivalents of cationically curable groups, less than 0.10 equivalents of acrylate groups and between less than 0.10 to about 0.03 equivalents of hydroxyl groups per 100 grams of said composition; (2) exposing said first layer to actinic radiation in a pattern corresponding to a respective cross-sectional layer of the model sufficient to harden the first layer in the imaged area; (3) forming a second layer of said composition above the hardened first layer; (4) exposing said second layer to actinic radiation in a pattern corresponding to a respective cross-sectional layer of the model sufficient to harden the second layer in the imaged area; and (5) repeating steps (3)-(4) to form successive layers as desired to form said thee-dimensional article.