Use of latent metathesis polymerization systems for additive manufacturing
The invention is directed to latent metathesis-active resin compositions and additive manufacturing approaches. The latent metathesis-active compositions comprise at least one latent metathesis catalyst, at least one curable metathesis-active monomer, and optional fillers, photosensitizers, and/or a secondary monomer resin system for dual-cure. A method comprises extruding a latent metathesis-active resin from a dispensing apparatus and spatially triggering a ring-opening metathesis polymerization by directed irradiation with light or directed application of a thermal stimuli for direct-ink write printing of objects. Another method uses a latent metathesis-active resin for vat photopolymerization and stereolithographic printing of objects.
1. A resin for direct ink write additive manufacturing, comprising:
a metathesis-active monomer;
a latent metathesis catalyst that can be activated by an external stimulus to initiate a ring-opening metathesis polymerization (ROMP) of the metathesis-active monomer; and
at least one filler that provides the resin with a shear-thinning property.
2. The resin of claim 1 , wherein the metathesis-active monomer comprises a cyclic olefin.
3. The resin of claim 2 , wherein the cyclic olefin comprises a norbornadiene, norbornene, oxonorbornene, azanorbornene, cyclobutene, cyclooctene, cyclooctadiene, cyclooctatetraene, dicyclopentadiene, or derivatives thereof.
4. The resin of claim 1 , wherein the latent metathesis catalyst comprises a thermally latent, photolatent, or a redox-latent ROMP catalyst.
5. The resin of claim 4 , wherein the latent metathesis catalyst comprises a ruthenium, tungsten, molybdenum, rhenium, or titanium catalyst.
6. The resin of claim 4 , wherein the latent metathesis catalyst comprises a ruthenium-based Grubbs catalyst.
7. The resin of claim 1 , wherein the resin comprises 0.01 to 1 mol % latent metathesis catalyst.
8. The resin of claim 1 , wherein the resin comprises 0.01 to 0.08 mol % latent metathesis catalyst.
9. The resin of claim 1 , further comprising at least one photosensitizer.
10. The resin of claim 9 , wherein the at least one photosensitizer comprises isopropylthioxanthone, camphorquinone, benzophenone, phenothiazine, benzil, Rose Bengal, rhodamine, or coumarin.
11. The resin of claim 9 , wherein the resin comprises less than 3 wt % photosensitizer.
12. The resin of claim 9 , wherein the resin comprises 1:1 to 16:1 wt/wt latent metathesis catalyst to photosensitizer.
13. The resin of claim 9 , further comprising a co-initiator that accelerates the rate of initiation of the photosensitizer.
14. The resin of claim 13 , wherein the co-initiator comprises ethyl 4-(dimethylamino)benzoate.
15. The resin of claim 1 , further comprising ethylidene norbornene.
16. The resin of claim 1 , wherein the at least one filler comprises silica, clay, fumed silica, zirconate, aluminate, or precipitated calcium carbonate.
17. The resin of claim 1 , wherein the at least one filler comprises a carbon or glass fiber, carbon nanotube, inorganic fiber or filler, or organic or natural fiber or filler.
18. The resin of claim 1 , further comprising a non-metathesis-active monomer to provide a dual-cure resin, wherein the non-metathesis-active monomer can be polymerized post-print by a non-ROMP process.
19. The resin of claim 18 , wherein the non-metathesis-active monomer comprises a thermally initiated monomer.
20. The resin of claim 19 , wherein the thermally initiated monomer comprises an epoxy monomer.
21. The resin of claim 18 , wherein the non-metathesis-active monomer comprises a photoinitiated monomer.
22. The resin of claim 21 , wherein the photoinitiated monomer comprises a free-radical acrylate monomer or a cationic/anionic polymerizable monomer.
23. A method for direct-ink write additive manufacturing, comprising:
providing the resin of claim 1 comprising a metathesis-active monomer and a latent metathesis catalyst;
extruding the resin through a nozzle;
depositing the extruded resin on a surface along a defined path;
activating the latent metathesis catalyst using an external stimulus to initiate a ring-opening metathesis polymerization (ROMP) of the metathesis-active monomer of the deposited resin to provide a layer of polymerized resin; and
printing a shape of polymerized resin layer-by-layer, thereby forming a printed object.
24. The method of claim 23 , wherein the external stimulus comprises a thermal or photo stimulus.
25. The method of claim 23 , further comprising post-print curing of the printed object.
26. A method for stereolithographic additive manufacturing, comprising
irradiating a bath of the resin of claim 1 with a targeted light exposure, thereby activating the latent metathesis catalyst to initiate a ring-opening metathesis polymerization (ROMP) of the metathesis-active monomer and forming a layer of polymerized resin, and
repeating the irradiating step to build a printed object layer-by-layer.
27. A method for additive manufacturing of dual-cure thermoset resins, comprising:
providing a resin of claim 1 , wherein the resin further comprises one or more non-metathesis-active monomers to provide a dual-cure resin;
extruding the dual-cure resin from direct-ink write apparatus along a defined path; and
photo or thermally activating the dual-cure resin, thereby initiating a latent ring-opening metathesis polymerization (ROMP) of the metathesis-active monomer, whereby a structure is printed layer-by-layer; and
polymerizing the one or more non-metathesis-active monomers in the printed structure by a non-ROMP process to provide a printed object.
28. The method of claim 27 , wherein the one or more non-metathesis-active monomers comprises a homopolymerized epoxy resin, an epoxy/amine resin, or an epoxy/anhydride resin.
29. The method of claim 27 , wherein the one or more non-metathesis-active monomers comprises a free-radical acrylate monomer or a cationic/anionic polymerizable monomer.