Toner composition, developer comprising the toner composition, and method in connection with the production of a volume body
The present invention relates to a toner composition for forming a masking pattern for use e.g. in connection with a method of building up a three-dimensional body from a large number of mutually connected layers of powder particles that are bonded to each other using radiant heat. The toner composition consists of powder particles that arc able to withstand a temperature of at least 200° C. without sticking together. It also relates to a developer that comprises the toner composition and carrier particles and a method in connection with the production of a volume body by using a toner composition or a developer according to the invention.
1. A toner composition adapted to be used in forming a masking pattern in a method of building up a three-dimensional body from a large number of mutually connected layers of powder particles that are bonded to each other using radiant heat, wherein
the toner composition consists of powder particles and at least a majority of the powder particles are made of a polymer material, a non-abrasive ceramic material selected from glass and talcum powder and/or a non-abrasive metal material, all of the powder particles having a Mohs-hardness of 8 or less,
the entire toner composition is able to withstand a temperature of at least 200° C. without the powder particles sticking together, and
the toner composition has the property that it absorbs and reflects incident electromagnetic radiation that impinges essentially perpendicularly onto the masking pattern wherein a toner layer having a thickness that corresponds to three particle mono-layers of powder particles has a radiation transmission of not more than 30%.
2. The toner composition according to claim 1 , wherein all of the powder particles have a glass transition temperature higher than 200° C.
3. The toner composition according to claim 2 , wherein the material of the powder particles is chosen such that the powder particles do not mechanically deform at temperatures greater than 200° C.
4. The toner composition according to claim 1 , wherein a toner layer having a thickness that corresponds to three particle mono-layers of the powder particles will result in a radiation transmission of not more than 20%.
5. The toner composition according to claim 1 , wherein the polymer material is chosen from a group that consists of fluoropolymers, polyimide (PI), polyethersulfone (PES) and polyetheretherketone (PEEK).
6. The toner composition according to claim 1 , wherein the non-abrasive metal material is chosen from gold, gold alloys, titanium, titanium alloys and stainless steel.
7. The toner composition according to claim 2 , wherein the powder particles carry, internally and/or externally, at least one of an absorbing material and a reflecting material.
8. The toner composition according to claim 7 , wherein the absorbing material consists of carbon black in an amount of 0.5-5% by weight.
9. The toner composition according to claim 7 , wherein the reflecting material consists of titanium dioxide in an amount of 4-10% by weight.
10. The toner composition according to claim 7 , further comprising silicon dioxide in an amount of 0.1-1% by weight.
11. The toner composition according to claim 1 , wherein the powder particles have an average diameter d50 in the range of 30-35 μm.
12. The toner composition according to claim 1 , wherein a major part of the powder particles has an average diameter d50 between 4 μm and 20 μm.
13. The toner composition according to claim 12 , wherein the powder particles have an average diameter d50 of about 10-15 μm.
14. A developer comprising a mixture of carrier particles and the toner composition according to claim 1 .
15. The developer according to claim 14 , wherein the carrier particles comprise magnetically-susceptible ferrite particles.
16. The developer according to claim 14 , wherein the carrier particles have a diameter that is 2-10 times larger than the diameter of the powder particles of the toner composition.
17. The developer according to claim 16 , wherein the toner particles make up 5-30% by weight of the toner composition-carrier mixture.
18. A method for producing a volume body of a large number of mutually connected layers of powder particles that are bonded to each other using radiant heat, wherein the method comprises:
forming a masking pattern using a toner composition according to claim 1 , the masking pattern preventing certain surface regions of an uppermost layer of a particulate material disposed adjacent to the masking pattern from being sintered or melted by the radiant heat,
removing the masking pattern, and
recirculating at least 50% of the removed toner composition.
19. A toner composition consisting essentially of powder particles made of a polymer material, a non-abrasive ceramic material selected from glass and talcum powder and/or a non-abrasive metal material,
wherein all of the powder particles have a Mohs-hardness of 8 or less, the entire toner composition is capable of withstanding a temperature of at least 200° C. without the powder particles adhering together, and a layer of the toner composition having a thickness of 100 microns transmits less than 25% of infra-red radiation through it.
20. A toner composition according to claim 19 , wherein the toner composition at least substantially comprises perfluoroalkoxy polymer (PFA) having a glass transition temperature of more than 200° C. and the toner composition further comprises 0.5-5% by weight of an infra-red absorbing material and 4-10% by weight of an infra-red reflecting material.
21. A toner composition according to claim 20 , wherein the infra-red absorbing material comprises carbon black, the infra-red reflecting material comprises titanium dioxide and the powder particles have an average diameter d50 of about 29-38 microns.
22. A developer comprising:
about 5-30% by total weight of the toner composition of claim 21 and about 70-95% by total weight of ferrite particles having a diameter that is 2-10 times larger than the diameter of the powder particles of the toner composition.
23. A method for forming a three-dimensional body from bonded-together layers of particulate material, the method comprising:
(a) forming a substantially non-transparent masking pattern on a masking device, the masking pattern comprising the toner composition of claim 21 ,
(b) disposing the masking device adjacent to an uppermost layer of the particulate material,
(c) applying infra red radiation to the masking device, whereby a portion of the uppermost layer of the particulate material that is not masked by the masking pattern is melt-bonded together,
(d) removing the masking pattern from the masking device, and
(e) reusing at least 50% of the toner composition of the removed masking pattern in a repetition of steps (a)-(d).
24. The toner composition according to claim 3 , wherein the toner composition at least substantially comprises perfluoroalkoxy polymer (PFA) and further comprises 0.5-5% by weight of carbon black and 4-10% by weight of titanium dioxide.