3D printing method utilizing heat-curable silicone composition
A method of forming a three-dimensional (3D) article comprises the steps of I) printing a first heat-curable silicone composition with a 3D printer to form a layer, II) heating the layer to form an at least partially cured layer, III) printing a second heat-curable silicone composition on the at least partially cured layer with the 3D printer to form a subsequent layer, and IV) heating the subsequent layer to form an at least partially cured subsequent layer. Optionally, steps III) and IV) can be repeated with independently selected heat-curable silicone composition(s) for any additional layer(s) to form the 3D article. The first and second heat-curable silicone compositions may be the same as or different from one another.
1. A method of forming a three-dimensional (3D) article, said method comprising:
I) printing a first heat-curable silicone composition with a 3D printer to form a layer, wherein the first heat-curable silicone composition is not heated during printing in I);
II) heating the layer to form an at least partially cured layer;
III) printing a second heat-curable silicone composition on the at least partially cured layer with the 3D printer to form a subsequent layer, wherein the second heat-curable silicone composition is not heated during printing in III);
IV) heating the subsequent layer to form an at least partially cured subsequent layer; and,
V) optionally, repeating steps III) and IV) with independently selected heat-curable silicone composition(s) for any additional layer(s) to form the 3D article;
wherein the first and second heat-curable silicone compositions are the same as or different from one another, wherein the first and second heat-curable silicone compositions are not cured via irradiation; and
wherein the first and second heat-curable silicone compositions are independently selected from condensation-curable silicone compositions, hydrosilylation-curable silicone compositions, free radical-curable silicone compositions, and dual-cure silicone compositions.
2. The method according to claim 1 , wherein steps II) and IV) are independently selected from (i) conductive heating via a substrate on which the layer is printed; (ii) heating the particular heat-curable silicone composition via the 3D printer or a component thereof; (iii) infrared heating; (iv) electromagnetic heating; (v) a heating bath with a heat transfer fluid; (vi) heating from an exothermic reaction of the particular heat-curable silicone composition; (vii) magnetic heating; or (viii) any combination of (i) to (vii).
3. The method according to claim 1 , wherein the first and second heat-curable silicone compositions are the same.
4. The method according to claim 1 , wherein the first and/or second heat-curable silicone composition(s) comprise(s) a hydrosilylation-curable silicone composition comprising (A) an organopolysiloxane having an average of at least two silicon-bonded alkenyl groups or silicon-bonded hydrogen atoms per molecule; (B) an organosilicon compound having an average of at least two silicon-bonded hydrogen atoms or silicon-bonded alkenyl groups per molecule capable of reacting with the silicon-bonded alkenyl groups or silicon-bonded hydrogen atoms in the organopolysiloxane (A); and (C) a hydrosilylation catalyst.
5. The method according to claim 1 , wherein the first and/or second heat-curable silicone composition(s) comprise(s) a condensation-curable silicone composition comprising (A′) an organopolysiloxane having an average of at least two silicon-bonded hydroxyl or hydrolysable groups per molecule; optionally (B′) an organosilicon compound having an average of at least two silicon-bonded hydrogen atoms, hydroxyl groups, or hydrolysable groups per molecule; and (C′) a condensation catalyst; and optionally, wherein the condensation-curable silicone composition is a multipart composition, wherein component (A′) is in a first part, component (B′) is in a second part separate from the first part, and component (C′) is in the second part and/or in a third part separate from the first and second parts.
6. The method according to claim 1 , wherein the first and/or second heat-curable silicone composition(s) comprise(s) a free radical-curable silicone composition comprising (A″) an organopolysiloxane having an average of at least two silicon-bonded unsaturated groups and (C″) an organic peroxide.
7. The method according to claim 1 , wherein the first and second heat-curable silicone compositions are different from one another.
8. The method according to claim 1 , wherein the first and/or second heat-curable silicone composition(s) is(are) a multi-part heat-curable silicone composition comprising at least a first part and a second part separate from the first part; and optionally, wherein the separate parts of the multi-part heat-curable silicone composition are mixed in a dual dispense printing nozzle prior to printing.
9. The method according to claim 1 , wherein the 3D printer is selected from a fused filament fabrication printer, a selective laser sintering printer, a selective laser melting printer, a stereolithography printer, a powder bed (binder jet) printer, a material jet printer, a direct metal laser sintering printer, an electron beam melting printer, a laminated object manufacturing deposition printer, a directed energy deposition printer, a laser powder forming printer, a polyjet printer, an ink-jetting printer, a material jetting printer, and a syringe extrusion printer.
10. The method according to claim 1 , wherein the at least partially cured layer formed in step II) retains its shape upon exposure to ambient conditions.
11. The method according to claim 1 , wherein heating via steps II) and IV) is carried out at a temperature independently selected from above ambient temperature to 300° C.
12. The method according to claim 1 , wherein the first and/or second heat-curable composition(s) is(are) shear thinning.
13. A 3D article formed in accordance with the method of claim 1 .