Methods of Making Three Dimensional Objects from Dual Cure Resins with Supported Second Cure

Abstract

A method of forming a three-dimensional object is carried out by: (a) providing a carrier and an optically transparent member having a build surface, the carrier and the build surface defining a build region therebetween; (b) filling the build region with a polymerizable liquid, the polymerizable liquid comprising a mixture of (i) a light polymerizable liquid first component, and (ii) a second solidifiable component that is different from the first component; and (c) irradiating the build region with light through the optically transparent member to form a solid polymer scaffold from the first component and also advancing the carrier away from the build surface to form a three-dimensional intermediate having the same shape as, or a shape to be imparted to, the three-dimensional object and containing the second solidifiable component carried in the scaffold in unsolidified and/or uncured form; then (d) supporting the three dimensional intermediate with a separate support media; then (e) solidifying and/or curing the second solidifiable component in the three-dimensional intermediate to form the three-dimensional object in the support media; and then (f) separating the support media from the three-dimensional object.

Claims

1. A method of forming a three-dimensional object, comprising: (a) providing a carrier and an optically transparent member having a build surface, said carrier and said build surface defining a build region therebetween; (b) filling said build region with a polymerizable liquid, said polymerizable liquid comprising a mixture of (i) a light polymerizable liquid first component, and (ii) a second solidifiable component that is different from said first component; and (c) irradiating said build region with light through said optically transparent member to form a solid polymer scaffold from said first component and also advancing said carrier away from said build surface to form a three-dimensional intermediate having the same shape as, or a shape to be imparted to, said three-dimensional object and containing said second solidifiable component carried in said scaffold in unsolidified and/or uncured form; then (d) supporting said three dimensional intermediate with a separate support media; then (e) solidifying and/or curing said second solidifiable component in said three-dimensional intermediate to form said three-dimensional object in said support media; and then (f) separating said support media from said three-dimensional object.

2. The method of claim 1, wherein said media is a solid particulate.

3. The method of claim 1, wherein said media is flowable.

4. The method of claim 1, wherein said media is inert and/or water soluble.

5. The method of claim 1, wherein said media comprises a microwave absorbing material.

6. The method of claim 1, wherein said media is comprised of an inorganic salt.

7. The method of claim 6, wherein said inorganic salt is selected from the group consisting of sodium chloride, sodium bicarbonate, sodium carbonate, sodium sulfate, sodium sulfite, sodium iodide, sodium bromide, magnesium sulfate, magnesium carbonate, magnesium bromide, magnesium iodide, calcium chloride, calcium carbonate, calcium bromide, calcium sulfate, calcium iodide, potassium carbonate, potassium chloride, potassium bromide, potassium iodide, potassium nitrate, ammonium sulfate, ammonium chloride, ammonium bromide, ammonium iodide, and combinations thereof.

8. The method of claim 5, wherein said separating step is carried out by dissolving or solubilizing said media with water.

9. The method of claim 1, wherein said solidifying and/or curing step (e) is carried out by heating and/or microwave irradiating.

10. The method of claim 1, wherein said three-dimensional intermediate is collapsible, compressible, or elastic.

11. The method of claim 1, wherein said filling and irradiating steps (b) and (c) are carried out by continuous liquid interface production (CLIP).

12. The method of claim 1, wherein said second component comprises: (i) a polymerizable liquid solubilized in or suspended in said first component; (ii) a polymerizable solid suspended in said first component; (iii) a polymerizable solid solubilized in said first component; or (iv) a polymer solubilized in said first component.

13. The method of claim 1, wherein said polymerizable liquid comprises: from 1 percent by weight to 99 percent by weight of said first component; and from 1 percent by weight to 99 percent by weight of said second component.

14. The method of claim 1, wherein said solidifying and/or curing step (e) is carried out subsequent to said irradiating step (c) and is carried out by: (i) heating said second solidifiable component; (ii) irradiating said second solidifiable component with light at a wavelength different from that of the light in said irradiating step (c); (iii) contacting said second solidifiable component to water; and/or (iv) contacting said second solidifiable component to a catalyst.

15. The method of claim 1, wherein: said second component comprises the precursors to a polyurethane, polyurea, or copolymer thereof, a silicone resin, an epoxy resin, a cyanate ester resin, or a natural rubber; and said solidifying step is carried out by heating.

16. The method of claim 1, wherein: said second component comprises the precursors to a polyurethane, polyurea, or copolymer thereof, and said solidifying and/or curing step is carried out by contacting said second component to water.

17. The method of claim 1, wherein said solidifying and/or curing step (e) is carried out under conditions in which said solid polymer scaffold degrades and forms a constituent necessary for the polymerization of said second component.

18. The method of claim 1, wherein: said second component comprises precursors to a polyurethane, polyurea, or copolymer thereof, a silicone resin, a ring-opening metathesis polymerization resin, or a click chemistry resin, a cyanate ester resin, and said solidifying and/or curing step is carried out by contacting said second component to a polymerization catalyst.

19. The method of claim 1, wherein said polymerizable liquid comprises said first component and at least one additional component, said first component comprising monomers and/or prepolymers that can be polymerized by exposure to actinic radiation or light; said second component solidifiable on contacting to heat, water, water vapor, light at a different wavelength than that at which said first component is polymerized, catalysts, evaporation of a solvent from the polymerizable liquid, exposure to microwave irradiation, and combinations thereof.

20. The method of claim 20, wherein said first component monomers and/or prepolymers comprise reactive end groups selected from the group consisting of acrylates, methacrylates, a-olefins, N-vinyls, acrylamides, methacrylamides, styrenics, epoxides, thiols, 1,3-dienes, vinyl halides, acrylonitriles, vinyl esters, maleimides, and vinyl ethers.

21. The method of claim 19, wherein said additional component comprises monomers and/or prepolymers comprising reactive end groups selected from the group consisting of: epoxy/amine, epoxy/hydroxyl, oxetane/amine, oxetane/alcohol, isocyanate/hydroxyl, isocyanate/amine, isocyanate/carboxylic acid, cyanate ester, anhydride/amine, amine/carboxylic acid, amine/ester, hydroxyl/carboxylic acid, hydroxyl/acid chloride, amine/acid chloride, vinyl/SiH, SiCl/hydroxyl, SiCl/amine, hydroxyl/aldehyde, amine/aldehyde, hydroxymethyl or alkoxymethyl amide/alcohol, aminoplast, alkyne/azide, click chemistry reactive groups, alkene/sulfur, alkene/thiol, alkyne/thiol, hydroxyl/halide, isocyanate/water, SiOH/hydroxyl, SiOH/water, SiOH/SiH, SiOH/SiOH, perfluorovinyl, diene/dienophiles, olefin metathesis polymerization groups, olefin polymerization groups for Ziegler-Natta catalysis, and ring-opening polymerization groups and mixtures thereof.

22. The method of claim 1, wherein: said three-dimensional object is comprised of polyurethane, polyurea, or copolymer thereof; and said polymerizable liquid is comprised of at least one of: (i) a blocked or reactive blocked prepolymer, (ii) a blocked or reactive blocked diisocyante, or (iii) a blocked or reactive blocked diisocyanate chain extender.

23. The method of claim 22, wherein said polymerizable liquid comprises: (a) a mixture of (i) a blocked or reactive blocked prepolymer, (ii) a chain extender, (iii) a photoinitiator, (iv) optionally a polyol and/or a polyamine, and (v) optionally a reactive diluent, (vi) optionally a pigment or dye, (vii) optionally a filler; or (b) a mixture of (i) a blocked or reactive blocked diisocyanate, (ii) a polyol and/or polyamine, (iii) a chain extender, (iv) a photoinitiator, and (v) optionally a reactive diluent (vi) optionally a pigment or dye, (vii) optionally a filler; or (c) a mixture of (i) a polyol and/or polyamine, (ii) a blocked or reactive blocked diisocyanate chain extender, (iii) optionally one or more additional chain extenders, (iv) a photoinitiator, and (v) optionally a reactive diluent (vi) optionally a pigment or dye, and (vii) optionally a filler.

24. The method of claim 1, wherein said three-dimensional object comprises a polymer blend, interpenetrating polymer network, semi-interpenetrating polymer network, or sequential interpenetrating polymer network formed from said first component and said second component.

25. The method of claim 1, wherein said three-dimensional object comprises an interpenetrating polymer network (IPN), said interpenetrating polymer network comprising a sol-gel composition, a hydrophobic-hydrophilic IPN, a phenolic resin, a polyimide, a conductive polymer, a natural product-based IPN, a sequential IPN, a semi IPN, a polyolefin, or a combination thereof.

26. The method of claim 1, wherein said irradiating and/or said advancing steps are carried out while also concurrently: (i) continuously maintaining a dead zone of polymerizable liquid in contact with said build surface, and (ii) continuously maintaining a gradient of polymerization zone between said dead zone and said solid polymer and in contact with each thereof, said gradient of polymerization zone comprising said first component in partially cured form.

27. The method of claim 26, wherein said optically transparent member comprises a semipermeable member, and said continuously maintaining said dead zone is carried out by feeding an inhibitor of polymerization through said optically transparent member, thereby creating a gradient of inhibitor in said dead zone and optionally in at least a portion of said gradient of polymerization zone.

28. The method of claim 1, wherein said optically transparent member comprises a fluoropolymer.

29. The method of claim 27, wherein: said first component comprises a free radical polymerizable liquid and said inhibitor comprises oxygen; or said first component comprises an acid-catalyzed or cationically polymerizable liquid, and said inhibitor comprises a base.

30. The method of claim 1, further comprising vertically reciprocating said carrier with respect to the build surface to enhance or speed refilling of the build region with the polymerizable liquid.

Description

EXAMPLE

Heat Cure of an Intermediate Part in Particulate Sodium Chloride Support

[0165] A polyurethane dual cure resin is used to produce a three-dimensional part by first forming an intermediate part by Continuous Liquid Interface Production (CLIP).

[0166] After being formed by CLIP, the intermediate part is separated from its carrier and washed in isopropyl alcohol (IPA) or, alternatively, an aqueous cleaner such as Rapid Rinse Prototype cleaner by Green Power Chemical, to remove surface resin. Support elements are removed from the part with clippers or razor blades. The part is placed in IPA and scrubbed with a soft bristle brush on all surfaces, with an additional focus on corners and difficult to reach areas. In the case of long hollow cylindrical geometries, a pipe cleaner may be utilized to remove excess resin.

[0167] The entire part is then sprayed with clean IPA and the part blown dry with pressurized air.

[0168] Once dry, the part is placed in a bed of SALTWORKS PURE OCEAN powdered sea salt (SaltWorks, Inc. 16240 Wood-Red Rd NE, Woodinville, Wash. 98072 USA) and covered generously with additional powdered salt, so that the entire part is fully engulfed, with all surfaces fully in contact with the salt.

[0169] The part, covered in salt, is then placed in an oven and baked for a sufficient amount of time that all salt heats to oven temperature and allows for full thermal cure of the part to occur (testing may be necessary to account for the time the thermal mass of salt requires to heat up to oven temperature. Initial estimates are that one metal 10 in10 in5 in pan filled with salt would require an additional 30 min to 1 hr.). The part is then removed from the oven and allowed to cool to room temperature. Of course, the part may be removed from the oven before the part itself reaches oven temperature if it is sufficiently cured beforehand.

[0170] Once cool, the part is removed from salt and run under warm water until all salt is dissolved from the surface of the part.

[0171] The foregoing is illustrative of the present invention, and is not to be construed as limiting thereof The invention is defined by the following claims, with equivalents of the claims to be included therein.