Polymer composition for selective sintering methods
A polymer composition can be used in selective absorbing sintering, SAS, or selective inhibition sintering, SIS, methods. The polymer of the polymer composition has open mesopores, where a cumulative pore volume distribution of the mesopores, measured according to DIN 66134, is at least 0.01 cm 3 /g.
1. A polymer composition for selective absorbing sintering, or selective inhibition sintering,
comprising:
a polymer comprising open mesopores, which is obtained by a precipitation process, and
a sintering absorber or a sintering inhibitor,
wherein a cumulative pore volume distribution of the mesopores, measured according to DIN 66134, is 0.01 to 0.127 cm 3 /g, and
wherein said polymer is a polyamide and
said absorber or said inhibitor is within open mesopores of said polymer.
2. The polymer composition according to claim 1 , wherein
the cumulative pore volume distribution is at least 0.025 cm 3 /g.
3. The polymer composition according to claim 1 , wherein
the cumulative pore volume distribution is at least 0.035 cm 3 /g.
4. The polymer composition according to claim 1 , wherein
at least 30% of a sum total of open macro- and mesopores of the polymer composition having a pore diameter of 2 to 300 nm, measured according to DIN 66134, are open mesopores.
5. The polymer composition according to claim 1 , wherein
at least 50% of a sum total of open macro- and mesopores of the polymer composition having a pore diameter of 2 to 300 nm, measured according to DIN 66134, are open mesopores.
6. The polymer composition according to claim 1 , wherein
a BET surface area of the polymer composition, measured to DIN ISO 9277, is at least 7 m 2 /g to 30 m 2 /g.
7. The polymer composition according to claim 1 , wherein
a BET surface area of the polymer composition, measured to DIN ISO 9277, is from 10 m 2 /g to 30 m 2 /g.
8. The polymer composition according to claim 1 , wherein
a weight average particle diameter d 50 of the polymer composition, measured by laser diffraction, is not more than 100 μm.
9. The polymer composition according to claim 1 , wherein
a weight average particle diameter d 50 of the polymer composition, measured by laser diffraction, is from 10 μm to 80 μm.
10. The polymer composition according to claim 1 , wherein
a surface energy of a polymer in the polymer composition is 25 to 35 mN/m, the surface energy determined by a contact angle measurement by a capillary rise height method using a Washburn equation and an evaluation method according to Owens, Wendt, Rabel and Kaelble.
11. The polymer composition according to claim 1 , wherein
a surface energy of a polymer in the polymer composition is from 25 mN/m to 32 mN/m, the surface energy determined by a contact angle measurement by a capillary rise height method using a Washburn equation and an evaluation method according to Owens, Wendt, Rabel and Kaelble.
12. The polymer composition according to claim 1 , which
absorbs a liquid in a volume of 1,000 pl/g to 30,000 pl/g.
13. A shaped body, which comprises the polymer composition according to claim 1 .
14. A shaped body, obtained by sintering the polymer composition according to claim 1 .
15. A process for producing a polymer composition according to claim 1 , the process comprising:
a) at least partly dissolving a polymer in a solvent at a temperature of 10 K to 60 K above a dissolution temperature of the polymer, and then
b) reducing the temperature down to a precipitation temperature to obtain the composition in the form of a suspension.
16. The process according to claim 15 , further comprising:
keeping the suspension, after precipitation, at a temperature of 2-10 K above the precipitation temperature for 10 min to 180 min.
17. The process according to claim 15 , wherein
said a) at least partly dissolving is effected at a dissolution temperature of 40 K to 60 K and the precipitation of said b) reducing is conducted at a temperature 3 K above the precipitation temperature or higher.
18. A process for producing a shaped body, the process comprising:
performing selective absorbing sintering or selective inhibition sintering with a polymer composition according to claim 1 to shape the polymer composition into the shaped body.