Sinterable feedstock for use in 3D printing devices
The present invention relates to a filament suitable to be used in a 3D printing device, wherein the filament comprises a metal and/or ceramic powder, a thermoplastic binder and additives. The invention also relates to a process for producing a shaped body comprising the step of printing a shaped green body using the filament according to the invention. Also provided is the use of a filament according to the invention in a 3D printing device and a green body producible by mixing a metal and/or ceramic powder and a thermoplastic binder. The invention also relates to the use of a binder of the invention for the production of a filament for 3D printing devices.
1. A 3D printing system comprising a filament, wherein the filament comprises
(a) a metal and/or ceramic powder;
(b) a thermoplastic binder comprising a thermoplastic polymer and at least one plasticizer; and
(c) from 0 to 10 wt % of additives based on the total weight of the filament,
wherein the at least one plasticizer is a mixture of esters, and wherein the mixture of esters comprises an ester which is solid at 20° C. and an ester that is liquid at 20° C., and
wherein the filament has a Shore A hardness of at least 85 at 20° C.
2. The 3D printing system according to claim 1 , wherein the metal and/or ceramic powder is sinterable.
3. The 3D printing system according to claim 1 , wherein the thermoplastic polymer is selected from the group consisting of a polyurethane, a polyamide, a polyvinylpyrrolidon, a polyacrylate, a polyolefin, and mixtures thereof.
4. The 3D printing system according to claim 3 , wherein the thermoplastic polymer is a polyamide, wherein the polyamide is selected from the group consisting of a copolyamide, Polyamide 11, Polyamide 12, a polyether-blockamide, and mixtures thereof.
5. The 3D printing system according to claim 1 , wherein the plasticizer is removable at least in part from the filament by extraction at a temperature of at least 20° C. using an organic solvent.
6. The 3D printing system according to claim 1 , wherein the at least one plasticizer is a substituted carboxylic acid ester, a non-substituted aromatic carboxylic acid ester, a heteroaromatic carboxylic acid ester, or mixtures thereof.
7. The 3D printing system according to claim 1 , wherein said at least one plasticizer is a mixture of hydroxybenzoic acid esters.
8. The 3D printing system according to claim 7 , wherein the hydroxybenzoic acid esters are esters of hydroxybenzoic acid and a branched or linear alcohol, wherein the alcohol is selected from the group consisting of a branched C8-C22 alcohol, a linear C8-C22 alcohol, and mixtures thereof.
9. The 3D printing system according to claim 7 , wherein the hydroxybenzoic acid esters are a p-hydroxybenzoic acid esters.
10. The 3D printing system according to claim 1 , wherein the thermoplastic binder comprises between 40 wt % and 70 wt % of the at least one plasticizer based on the total weight of the binder.
11. The 3D printing system according to claim 1 , wherein the thermoplastic binder has a melting temperature of between 100° C. and 190° C.
12. The 3D printing system according to claim 1 , wherein the filament is elastic, has a diameter of between 0.5 mm and 5 mm, and has a length of at least 10 cm.
13. The 3D printing device according to claim 1 , wherein the filament comprises
(a) from 80 to 95 wt % of the metal and/or ceramic powder based on the total weight of the filament of
(b) from 2 to 8 wt % of the thermoplastic polymer based on the total weight of the filament and from 1 to 5 wt % of the at least one plasticizer based on the total weight of the filament, and (c) from 0 to 1 wt % of additives based on the total weight of the filament, wherein the sum of the listed ingredients is 100 wt %, based on the total weight of the filament.
14. The 3D printing system according to claim 1 , wherein the Shore A hardness is measured in accordance to DIN ISO 7619-1 standard using a HPEII hardness tester.