Support material formulation and additive manufacturing processes employing same

A method of fabricating a three-dimensional model object, the method comprising dispensing a building material so as to sequentially form a plurality of layers in a configured pattern corresponding to the shape of the object, wherein said building material comprises a modeling material formulation and a support material formulation, and wherein said support material formulation comprises:

• a non-curable water-miscible polymer, in an amount that ranges from 30 to 80 weight percent of the total weight of the formulation, said non-curable water-miscible polymer comprising an alkoxylated polyol;
• a non-curable water-miscible non-polymeric material which comprises 1,2-propanediol;
• a first water-miscible, curable material in an amount that ranges from 10 to 20 weight percent of the total weight of the formulation;
• and
• at least one second water-miscible curable material in an amount that ranges from 5 to 15 weight percent of the total weight of the formulation,
• wherein said first water-miscible curable material comprises a mono-functional poly(alkylene glycol) acrylate;
• and
• wherein said second water-miscible curable material is represented by Formula I:
• wherein:
• Ra is selected from H, C(1-4) alkyl and a hydrophilic group;
• k is an integer ranging from 2 to 10;
• X is -NRc-, wherein Rc is hydrogen, alkyl, cycloalkyl or aryl;
• and
• Y is a hydrogen bond-forming moiety that comprises at least one nitrogen and/or oxygen atom,
• the support material formulation being devoid of a multi-functional curable material.