Siloxane additive manufacturing composition

An additive manufacturing composition comprising:

• at least one alkenyl-derivatized polysiloxane and at least one mercapto-derivatized polysiloxane crosslinking agent of formula (I):
• R1(R)2SiO((R3R4)SiO)xSi(R)2R2 (I),
• wherein R is independently C(1-12)alkyl, preferably methyl;
• R1, R2, R3, R4 are independently C(1-12)alkyl, preferably methyl, or mercapto-C(1-12)alkyl;
• x is 1 or more;
• with the proviso that at least one of R1, R2, R3, R4 is mercapto-C(1-12)alkyl, and wherein the alkenyl-derivatized polysiloxane and the mercapto-derivatized polysiloxane crosslinking agent form a stable emulsion;
• wherein the alkenyl-derivatized polysiloxane forms a continuous phase of the emulsion and the mercapto-derivatized polysiloxane crosslinking agent forms a discontinuous phase, wherein the discontinuous phase is present as droplets having a diameter of no more than 100 micrometers.