Patent ID: 7332537

Claim:
A three dimensional printing composition, comprising: a dry, loose, free-flowing particulate material including: about 10% to about 50% by weight of a particulate water-soluble adhesive material; 0% to about 20% by weight of a first fibrous component; semihydrate of calcium sulfate; an accelerator; and a filler, further characterized by absence of a retardant wherein the particulate material comprises particles having a mean diameter of about 10 microns to about 100 microns, and is suitable for use in three dimensional printing to form an article comprised of a plurality of layers, the layers including a reaction product of the particulate material and a aqueous fluid that contacts the particulate material during three dimensional printing, the particulate material being capable of supporting the article during three dimensional printing and suitable for being spread in a layer of dry particles having a thickness selected from a range of about 12 to about 125 microns.