A materials system and methods are provided to enable the formation of articles by three dimensional printing. The materials system includes particulate mixtures having a whitening agent and a solid particulate additive comprising an acid, the latter adapted for modifying a cure rate of an infiltrant....http://www.google.de/patents/US8167999?utm_source=gb-gplus-sharePatent US8167999 - Three-dimensional printing material system with improved color, article performance, and ease of use
