Thixotropic polysiloxane pastes for additive manufacturing

Abstract

Shelf-stable, rapid crosslinking, “all-in-one” pastes useful as “inks” in additive manufacturing are provided. These pastes exhibit desirable rheological flow properties and crosslinking upon exposure to UV light. The pastes are based on vinylsilyl-functionalized, completely amorphous, linear terpolysiloxanes containing predominantly dimethylsiloxy-repeat units with small amounts of diphenylsiloxy-, methylphenylsiloxy-, diethylsiloxy-, and/or methyltrifluoroalkylsiloxy-crystallization disruptors. The base polymers are preferably compounded with a trimethylsilylated-hydrophobic silica filler, thixotropic flow agent, hydrosilyl-functionalized oligomeric crosslinker, and a catalytic system comprising platinum(II) acetylacetonate or trimethyl(methylcyclopentadienyl)-platinum(IV), and diethyl azodicarboxylate.