THREE-DIMENSIONAL PRINTING
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.
1 .- 6 . (canceled)
7 . A multi-fluid kit for three-dimensional printing, comprising:
a binder fluid including water, and acrylic-based polymer particles in an amount ranging from about 1 wt % to about 40 wt % based on the total weight of the binder fluid; and
an adhesion promoter fluid including water, and a curable polyurethane adhesion promoter in an amount ranging from about 0.1 wt % to about 15 wt % based on the total weight of the adhesion promoter fluid, the curable polyurethane adhesion promoter being a reaction product of:
(a) a polyisocyanate;
(b) 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;
(c) 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
(d) a sulfonate or sulfonic acid having one or two hydroxyl functional groups or one or two amino functional groups.
8 . The multi-fluid kit as defined in claim 7 wherein the acrylic-based polymer particles have a glass transition temperature higher than 60° C. and an average particle size of 1 nm or more.
9 . The multi-fluid kit as defined in claim 7 wherein the curable polyurethane adhesion promoter is a reaction product of components (a), (b), (c), (d), and:
(e) a polyol having two or more hydroxyl functional groups and a number average molecular weight ranging from about 50 g/mol to about 6,000 g/mol; or
(f) an other acrylate or methacrylate having one hydroxyl functional group or one amino functional group, or an acrylamide or methacrylamide having one hydroxyl functional group; or
(g) a homopolymer or copolymer of poly(ethylene glycol) having one or two hydroxyl functional groups or one or two amino functional groups, a number average molecular weight ranging from about 500 g/mol to about 3,000 g/mol, and a water solubility greater than 30% v/v; or
any combination of (e), (f), and (g).
10 . The multi-fluid kit as defined in claim 7 wherein the sulfonate or sulfonic acid is selected from the group consisting of taurine, 4-Aminotoluene-3-sulfonic acid, Aniline-2-sulfonic acid, Sulfanilic acid, 4-Amino-1-naphthalenesulfonic acid, 3-Amino-4-hydroxybenzenesulfonic acid, 2-Amino-1-naphthalenesulfonic acid, 5-Amino-2-methoxybenzenesulfonic acid, 2-(Cyclohexylamino)ethanesulfonic acid, 3-Amino-1-propanesulfonic acid, aminoethylaminopropylsulfonic acid, N, N-Bis(2-hydroxyethyl)taurine, 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid, and aminoethylaminoethylsulfonate sodium salt.
11 . A method of three-dimensional printing, comprising:
iteratively applying individual build material layers of 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;
based on a 3D object model, selectively applying water, and a curable polyurethane adhesion promoter to individual build material layers to define individually patterned layers; and
heating all of the individually patterned layers to form a crosslinked network of the curable polyurethane adhesion promoter among the metal particles in patterned portions of all of the individually patterned layers, thereby forming a 3D intermediate object.
12 . The method as defined in claim 11 , further comprising selectively applying acrylic-based polymer particles to the individual build material layers.
13 . The method as defined claim 12 wherein:
the acrylic-based polymer particles are selectively applied by ejecting a binder fluid including water and the acrylic-based polymer particles in an amount of from about 1 wt % to about 40 wt % based on a total weight of the binder fluid; and
the curable polyurethane adhesion promoter is selectively applied by ejecting an adhesion promoter fluid as a separate fluid relative to the binder fluid, wherein the adhesion promoter fluid includes water and the curable polyurethane adhesion promoter in an amount of about 0.1 wt % to about 15 wt % based on the total weight of the adhesion promoter fluid.
14 . The method as defined of claim 12 wherein the acrylic-based polymer particles and the curable polyurethane adhesion promoter are selectively applied by ejecting a binder fluid including water, the acrylic-based polymer particles in an amount of from about 1 wt % to about 40 wt % based on a total weight of the binder fluid, and the curable polyurethane adhesion promoter in an amount of from about 0.05 wt % to about 5 wt % based on the total weight of the binder fluid.
15 . The method as defined in claim 11 wherein:
the heating occurs at a temperature ranging from about 120° C. to about 200° C.; and
the method further comprises:
separating the 3D intermediate object from non-patterned particulate build material; and
heating the 3D intermediate object at higher temperatures to remove the crosslinked network therefrom and sinter the metal particles thereof.
16 . The multi-fluid kit as defined in claim 7 wherein the component (a) is selected from the group consisting of hexamethylene-1,6-diisocyanate and isophoronediisocyanate.
17 . The multi-fluid kit as defined in claim 7 wherein the component (b) is selected from the group consisting of bisphenol A glycerolate diacrylate, 3-(acryloxy)-2-hydroxypropyl methacrylate, hydroxybutylacrylate, and pentaerythritol triacrylate.
18 . The multi-fluid kit as defined in claim 7 wherein the component (d) is selected from the group consisting of 3-(2-aminoethylamino)-propanesulfonic acid and taurine.
19 . The multi-fluid kit as defined in claim 7 wherein the component (d) is present in an amount ranging from about 2 wt % to about 20 wt % based upon the total weight of the curable polyurethane adhesion promoter.
20 . The multi-fluid kit as defined in claim 7 wherein the amount of component (c) is 0 wt %, and wherein component (d) is taurine.
21 . The multi-fluid kit as defined in claim 20 wherein the taurine is present in an amount ranging from about 10 wt % to about 20 wt % of the curable polyurethane adhesion promoter.
22 . The multi-fluid kit as defined in claim 7 wherein the amount of the component (c) is greater than 0 wt %, and wherein the component (c) is selected from the group consisting of 2,2-bis(hydroxymethyl)propionic acid and alanine.
23 . The multi-fluid kit as defined in claim 7 wherein the adhesion promoter fluid is separate from the binder fluid.
24 . The multi-fluid kit as defined in claim 7 wherein the binder fluid is devoid of a colorant.