METHOD FOR PRODUCTION OF COATED FILAMENTS FOR EXTRUSION-BASED 3D PRINTING PROCESSES
The present invention relates to a novel process for the production of coated filaments for subsequent application as print in extrusion-based 3D printers, e.g. FDM printers (fused deposition modelling printers). The filaments are coated in a separate process outside of the printer, and can also be used in a conventional extrusion printer. The present invention further relates to the coating device for application of the coating to the filament and to a roll containing the coated filaments.
1 . A method to prepare coated filaments, comprising:
supplying a solid filament in a form of a strand to a coating unit;
applying a coating composition comprising at least one of a pigment, an ink and an additive to the solid filament in the coating unit;
controlling the thickness of the coating on the solid filament; and
fixing the coating on the surface of the solid filament to obtain the coated filament;
wherein
the solid filament comprises a thermoplastically processable material, an acid soluble polymer, a base soluble polymer or a water soluble polymer, and
the coated filament is suitable for printing in a 3D extrusion process.
2 . The method according to claim 1 , wherein the filament comprises a thermoplastically processable material which is selected from the group consisting of acrylonitrile-butadiene-styrene terpolymer (ABS), polycarbonate (PC), poly(meth)acrylate, polyphenylene sulphone (PPSU), high density polyethylene (HDPE), polyetherimide (PEI), polyether ether ketone (PEEK), polylactic acid (PLA) and a mixture thereof.
3 . The method according to claim 1 , wherein applying the coating composition comprises at least one application technology selected from the group consisting of a nozzle application, application by a sponge material which surrounds the filament, application of the coating through an annular gap, and microextrusion.
4 . The method according to claim 3 , wherein application of the coating comprises microextrusion and the coating is applied as a melt onto the surface of the filament.
5 . The method according to claim 1 , wherein the coating application is controlled with a metering device.
6 . The method according to claim 1 , wherein fixing the coating on the surface of the filament comprises at least one fixing method selected from the group consisting of thermal drying, application of a jet of air, application of a jet of a gas other than air, plasma treatment, UV irradiation, microwave radiation and magnetic induction.
7 . The method according to claim 1 , further comprising winding the coated filament onto rolls for transport and storage.
8 . The method according to claim 1 , wherein the solid filament comprises an acid soluble polymer, a base soluble polymer or a water soluble polymer, and the coated filament is suitable as a support material for a 3D extrusion printed object.
9 . The method according to claim 1 , wherein the coating composition comprises an additive which is act vatable by microwaves, heat, plasma, UV light or magnetic fields.
10 . The method according to claim 1 , wherein the coating composition further comprises at least one of an adhesion promoter and adhesive.
11 . The method according to claim 1 , wherein the coating composition does not comprise a pigment or an ink and is colorless.
12 . The method according to claim 1 , wherein the coating is uniform on the filament strand.
13 . The method according to claim 1 , wherein the coating is not uniform on the filament strand.
14 . The method according to claim 1 , wherein the coating is not uniform and comprises different colors on the filament strand.
15 . A coated filament obtained according to the method of claim 1 .
16 . A coated filament obtained according to the method of claim 2 .
17 . A coated filament obtained according to the method of claim 8 .
18 . A coated filament obtained by the method of claim 10 .
19 . A roll obtained according to claim 7 .