Abstract: In an example of a method for three-dimensional (3D) printing, a polymeric build material is applied to form a build material layer. A fusing agent is selectively applied, based on a 3D object model, onto the build material layer to form a patterned portion. A hydrophobic agent is selectively applied, based on the 3D object model, onto at least a portion of the patterned portion. The hydrophobic agent includes a lipophilic phase discontinuously dispersed within an aqueous phase by a surfactant, wherein the lipophilic phase includes an organosilane having a central silicon atom coupled to a C6 to C24 aliphatic or alicyclic hydrocarbon and multiple hydrolyzable groups, wherein the organosilane is present in the hydrophobic agent at from about 1 wt % to about 20 wt %. The build material layer is exposed to energy to selectively coalesce the patterned portion and form a 3D object layer having a hydrophobic portion.

Abstract: A multi-fluid kit for three-dimensional printing can include a fusing agent with water and a radiation absorber, and a detailing agent. The radiation absorber can absorb radiation energy and converts the radiation energy to heat. The detailing agent can include water and from about 0.1 wt % to about 20 wt % organosilanes based on a total weight of the detailing agent, wherein the organosilanes include an organosilane compound with a central silicon having both a water-solubilizing group and multiple hydrolyzable groups attached thereto.

Abstract: In an example of a surface treatment method, a three-dimensionally printed polyamide object is used. In the surface treatment method, the three-dimensionally printed polyamide object is first exposed to benzyl alcohol. In the surface treatment method, the three-dimensionally printed polyamide object is exposed to microwave irradiation after the benzyl alcohol exposure.

Abstract: An example of a multi-fluid kit for three-dimensional (3D) printing includes a fusing agent and a surface treating agent. The fusing agent includes an electromagnetic radiation absorber and a first aqueous vehicle. The surface treating agent includes a second aqueous vehicle, a surfactant, and benzyl alcohol dissolved in the second aqueous vehicle.

Abstract: An example of a jettable antioxidant formulation is for three-dimensional (3D) printing. The jettable antioxidant formulation includes an antioxidant blend; a surfactant, a dispersant, or a combination thereof; a water soluble or water miscible organic co-solvent; and water. The antioxidant blend consists of a primary antioxidant and a secondary antioxidant.

Abstract: An example of a multi-fluid kit for three-dimensional (3D) printing kit includes a fusing agent and a build material reactive functional agent. The fusing agent includes water and an electromagnetic radiation absorber. The build material reactive functional agent includes a vehicle and trifluoroacetic anhydride. The multi-fluid kit may also be part of a 3D printing kit.

Abstract: The present disclosure is drawn to food contact compliant three-dimensional printing kits, materials, compositions, systems, and methods. In one example, a multi-fluid kit of food contact compliant agents for three-dimensional printing can include a food contact compliant fusing agent and a food contact compliant detailing agent. The food contact compliant fusing agent can include from about 70 wt% to about 96 wt% water, from about 3 wt% to about 10 wt% by solids weight of a food contact compliant carbon black dispersion, and from about 1 wt% to about 25 wt% of a food contact compliant water-soluble first co-solvent. The food contact compliant detailing agent can include from about 75 wt % to about 99 wt% water and from about 0.01 wt% to about 1 wt% of a food contact compliant chelating compound.

Abstract: The present disclosure is drawn to food contact compliant three-dimensional printing kits, materials, compositions, systems, and methods. In some examples, described herein is an example of a multi-fluid kit for three-dimensional printing comprising: a food contact compliant fusing agent comprising: at least about 70 wt % water based on the total weight of the food contact compliant fusing agent, food contact compliant carbon black dispersion in an amount of from about 3 wt % to about 10 wt % based on the total weight of the food contact compliant fusing agent, and at least one food contact compliant water soluble first co-solvent present in the food contact compliant fusing agent in an amount of from about 1 wt % to about 25 wt % based on the total weight of the food contact compliant fusing agent.

Abstract: In an example of a method for three-dimensional (3D) printing, a polymeric build material is applied to form a build material layer. A fusing agent is selectively applied, based on a 3D object model, onto the build material layer to form a patterned portion. A hydrophobic agent is selectively applied, based on the 3D object model, onto at least a portion of the patterned portion. The hydrophobic agent includes a perfluorinated polymer having a mean particle size ranging from about 50 nm to about 195 nm. The build material layer is exposed to energy to selectively coalesce the patterned portion and form a 3D object layer having a hydrophobic portion.

Abstract: In an example of a method for three-dimensional (3D) printing, a polymeric build material is applied to form a build material layer. A fusing agent is selectively applied, based on a 3D object model, onto the build material layer to form a patterned portion. A hydrophobic agent is selectively applied, based on the 3D object model, onto at least a portion of the patterned portion. The hydrophobic agent includes a lipophilic phase discontinuously dispersed within an aqueous phase by a surfactant, wherein the lipophilic phase includes an organosilane having a central silicon atom coupled to a C6 to C24 aliphatic or alicyclic hydro-carbon and multiple hydrolyzable groups, wherein the organosilane is present in the hydrophobic agent at from about 1 wt % to about 20 wt %. The build material layer is exposed to energy to selectively coalesce the patterned portion and form a 3D object layer having a hydrophobic portion.

Abstract: A multi-fluid kit for three-dimensional printing can include a fusing agent with water and a radiation absorber, and a detailing agent. The radiation absorber can absorb radiation energy and converts the radiation energy to heat. The detailing agent can include water and from about 0.1 wt % to about 20 wt % organosilanes based on a total weight of the detailing agent, wherein the organosilanes include an organosilane compound with a central silicon having both a water-solubilizing group and multiple hydrolyzable groups attached thereto.