Abstract: An example three-dimensional (3D) printing kit includes a particulate build material, which includes from about 80 wt % to 100 wt % metal particles based on a total weight of the particulate build material. In some examples, the kit also includes a binder fluid, which includes water and a curable polyurethane adhesion promoter in an amount ranging from about 0.5 wt % to about 15 wt % based on a total weight of the binder fluid. The curable polyurethane adhesion promoter is formed from a polyisocyanate; an acrylate or methacrylate, the acrylate or methacrylate having at least one hydroxyl functional group and having an acrylate functional group or a methacrylate functional group; a carboxylic acid including one or two hydroxyl functional groups, an amount of the carboxylic acid ranging from 0 wt % to about 10 wt %; and a sulfonate or sulfonic acid having one or two hydroxyl functional groups or one or two amino functional groups.

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: An example of a method for making a build material composition for three-dimensional (3D) printing includes freezing a dispersion of flow additive nanoparticles in a liquid to form a frozen liquid containing the flow additive nanoparticles. The frozen liquid containing the flow additive nanoparticles is lyophilized to form flow additive agglomerates having a porous, fractal structure. The flow additive agglomerates are mixed with a host metal. The flow additive nanoparticles have an average flow additive particle size ranging from about 1 to about 3 orders of magnitude smaller than an average host metal particle size of the host metal.

Abstract: The present disclosure is drawn to aqueous pigment dispersions. In one example, an aqueous pigment dispersion can include from 40 wt % to 90 wt % water, from 2 wt % to 30 wt % organic co-solvent, from 7.5 wt % to 30 wt % copper phthalocyanine pigment, from 0.5 wt % to 5 wt % styrene-acrylic dispersant, and from 0.5 wt % to 5 wt % hydrophilic polyurethane dispersant having a weight average molecular weight from 10,000 Mw to 30,000 Mw. The styrene-acrylic dispersant and the hydrophilic polyurethane dispersant can be present at a weight ratio from 1:10 to 2:1.

Abstract: A three-dimensional printing kit can include a particulate build material including from about 80 wt % to 100 wt % metal particles based on the total weight of the particulate build material, and a binder fluid. The binder fluid can include water, latex particles in an amount of from about 1 wt % to about 40 wt % based on the total weight of the binder fluid, and a multihydrazide adhesion promoter in an amount of from about 0.05 wt % to about 3 wt % based on the total weight of the binder fluid.

Abstract: An example of a method for making a build material composition for three-dimensional (3D) printing includes freezing a dispersion of flow additive nanoparticles in a liquid to form a frozen liquid containing the flow additive nanoparticles. The frozen liquid containing the flow additive nanoparticles is lyophilized to form flow additive agglomerates having a porous, fractal structure. The flow additive agglomerates are mixed with a host metal. The flow additive nanoparticles have an average flow additive particle size ranging from about 1 to about 3 orders of magnitude smaller than an average host metal particle size of the host metal.

Abstract: A three-dimensional printing kit can include a polymeric build material including thermoplastic elastomeric particles having a D50 particle size from about 2 ?m to about 150 ?m, and a fusing agent. The fusing agent can include water, from about 5 wt % to about 40 wt % lower alkyldiol organic co-solvent, and a radiation absorber to generate heat from absorbed electromagnetic radiation.

Abstract: The present disclosure describes multi-fluid kits for three-dimensional printing, three-dimensional printing kits, and methods of three-dimensional printing. In one example, a multi-fluid kit for three-dimensional printing can include a binder agent and an adhesion promoter agent. The binder agent can include water and latex particles in an amount from about 5 wt % to about 30 wt % based on the total weight of the binder agent. The adhesion promoter can include water and an adhesion promoter that includes catechol or a non-polymeric catechol derivative.

Abstract: A materials kit for three-dimensional (3D) printing can include a powder bed material comprising thermoplastic polyurethane particles and a fusing agent including a radiation absorber to selectively apply to the powder bed material. The thermoplastic polyurethane particles can have an average particle size from about 20 ?m to about 120 ?m and a melting temperature of from about 100° C. to about 250° C., wherein the thermoplastic polyurethane particles include polyurethane polymer strands having an average of about 10 wt % to about 30 wt % hard segments based on a total weight of the thermoplastic polyurethane particles. The hard segments can include a symmetrical aliphatic diisocyanate and a symmetrical aliphatic chain extender that are polymerized into the thermoplastic polyurethane particles.

Abstract: An example of a multi-fluid kit for three-dimensional printing includes a binder fluid and an adhesion promoter fluid. The binder fluid includes water and polymer particles in an amount ranging from about 1 wt % to about 40 wt % based on the total weight of the binder fluid. The adhesion promoter fluid includes water and an aromatic dihydrazide adhesion promoter in an amount ranging from about 0.1 wt % to about 10 wt % based on a total weight of the adhesion promoter fluid.

Abstract: The present disclosure describes multi-fluid kits for printing three-dimensional green body objects, three-dimensional printing kits, and methods of three-dimensional printing. In one example, a multi-fluid kit for printing a three-dimensional green body object can include an adhesion promoter agent and a binder agent. The adhesion promoter agent can include water and a dihydrazide compound. The binder agent can include water, an organic co-solvent, a glycidyl compound having two or more glycidyl groups per molecule, and latex particles. The latex particles can include polymerized monomers. The polymerized monomers can include a first monomer having an acid group and a second monomer having a vinyl group and without an acid group.

Abstract: The present disclosure describes binder agents for printing three-dimensional green body objects, three-dimensional printing kits, and methods of three-dimensional printing. In one example, a binder agent for printing a three-dimensional green body object can include water, an organic co-solvent, a glycidyl compound having two or more glycidyl groups per molecule, and latex particles. The latex particles can include polymerized monomers. The polymerized monomers can include a first monomer having an acid group, and a second monomer having a vinyl group and without an acid group.

Abstract: The present disclosure describes binder agents for printing three-dimensional green body objects, which can include water, an organic co-solvent, a nonionic surfactant, a dihydrazide compound, and latex particles. The nonionic surfactant can include two hydrophilic head groups and two hydrophobic tail groups per molecule.

Abstract: The present disclosure describes multi-fluid kits for three-dimensional printing, three-dimensional printing kits, and methods of three-dimensional printing. In one example, a multi-fluid kit for three-dimensional printing can include a binder agent and an adhesion promoter agent. The binder agent can include water and latex particles in an amount from about 5 wt % to about 30 wt % based on the total weight of the binder agent. The adhesion promoter can include water and an adhesion promoter that includes catechol or a non-polymeric catechol derivative.

Abstract: A polyurethane-based binder dispersion is described. The polyurethane based binder dispersion comprises: a polyurethane, which comprises: (A) a polyisocyanate; (B) a first polyol having a chain with two hydroxyl functional groups at one end of the chain and no hydroxyl groups at an opposed end of the chain; (C) a second polyol having a chain with two hydroxyl functional groups at both ends of the chain; (D) a carboxylic acid functional group with two hydroxyl functional groups; and (E) a compound shown in formula (1): m(M+) n(X)—R—Y— (1), wherein m is 0 or 1, M is a metal, n is 2 to 10, X is an amino group, R is a C1 to C18 alkyl group, a C6 to C30 aromatic compound or a C4 to C20 aliphatic cyclic compound, and Y is SO3- or SO3H, with the proviso that when m is 0, Y is SO3H and when m is 1, Y is SO3-.

Abstract: An example of a three-dimensional printing kit includes a particulate build material including from about 80 wt % to 100 wt % metal particles based on a total weight of the particulate build material. The three-dimensional printing kit further includes a binder fluid including water and polymer particles in an amount ranging from about 1 wt % to about 40 wt % based on a total weight of the binder fluid. The polymer particles have from about 1% to about 10% of a phosphate functional group.

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: The present disclosure describes three-dimensional printing kits, systems for three-dimensional printing, and methods of three-dimensional printing. In one example, a three-dimensional printing kit can include a particulate build material and a binding agent. The particulate build material can include metal particles. The binding agent can include a polyhydroxy polyol and a water-dispersible blocked polyisocyanate having multiple blocked isocyanate groups. The blocked isocyanate groups can include a blocking group bonded to the carbon atom of the blocked isocyanate group through a labile bond breakable by heating to a deblocking temperature. Breaking the labile bond can produce a released blocking group reacted with hydrogen and an isocyanate group.

Abstract: Examples of a three-dimensional (3D) printing kit include a particulate build material and a binder fluid. The particular build material includes from about 80 wt % to 100 wt % metal particles based on a total weight of the particulate build material. In some examples, the binder fluid includes water, polymer latex particles in an amount ranging from about 1 wt % to about 40 wt % based on a total weight of the binder fluid, and a silane coupling agent adhesion promoter in an amount ranging from about 0.05 wt % to about 3 wt % based on the total weight of the binder fluid. In some other examples, the binder fluid includes water and polymer latex particles, and the 3D printing kit further includes an adhesion promoter fluid which includes water and the silane coupling agent adhesion promoter.

Abstract: An example of a multi-fluid kit for three-dimensional printing includes a binder fluid and an adhesion promoter fluid. The binder fluid includes water and polymer particles in an amount ranging from about 1 wt % to about 40 wt % based on the total weight of the binder fluid. The adhesion promoter fluid includes water and an aromatic dihydrazide adhesion promoter in an amount ranging from about 0.1 wt % to about 10 wt % based on a total weight of the adhesion promoter fluid.