| CPC C09C 1/3081 (2013.01) [B29C 64/106 (2017.08); C08K 3/36 (2013.01); C08K 9/06 (2013.01); C08K 9/08 (2013.01); B33Y 10/00 (2014.12); B33Y 70/10 (2020.01); C01P 2006/22 (2013.01)] | 7 Claims |

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1. A method of forming a three-dimensional object, comprising:
a) contacting a substrate with a reservoir of prepolymer composition, the prepolymer composition comprising a resin comprising monomers and oligomers of polymers selected from acrylates, methacrylates, vinyl polymers, olefins, silicones, and epoxies and silica-containing particles selected from i) 0.1-50 wt % colloidal silica particles having a particle size of 5 nm-600 nm treated with at least one surface treatment agent, and ii) 0.1-50 wt % silica-polymer composite particles having a particle size of 10 nm-3 microns and comprising colloidal silica particles treated with at least one surface treatment agent, wherein the surface treatment agent comprises an organopolysiloxane, an organosiloxane, an organosilane, a haloorganosilane, or an organosilazane, and wherein the prepolymer composition has a viscosity no more than 500 cP greater than the neat resin at a temperature of 25° C. and a shear rate of 100 s−1;
b) selectively exposing the prepolymer composition imagewise to actinic radiation to form solid polymer at the substrate and having a build surface parallel to the substrate, the solid polymer being a sequential portion of the three-dimensional object;
c) contacting the build surface with the prepolymer composition;
d) selectively exposing the prepolymer composition to actinic radiation to increase the mass of the solid polymer, the additional polymer being a subsequent sequential portion of the three-dimensional object and
e) repeating steps c) and d) until the three dimensional object is formed.
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