Powder bed fusion material and method

1. A particulate material for powder bed fusion, comprising, based on the total weight of the particulate material,

97.4 to 99.98 weight percent of a thermoplastic selected from the group consisting of semicrystalline polycarbonates and semicrystalline polyetherimides; and

0.02 to 0.6 weight percent of a sulfonate salt having the structure

wherein Z is a phosphorus atom or a nitrogen atom; each occurrence of X is independently halogen or hydrogen provided that at least one X is halogen; b, d, and e are integers from zero to 12; c is 0 or 1 provided that when c is 1, d and e are not both zero; R 11 -R 13 are each independently C 1 -C 12 hydrocarbyl; R 14 is C 1 -C 18 hydrocarbyl; and Y is selected from

wherein R 15 is hydrogen or C 1 -C 12 hydrocarbyl;

wherein the particulate material comprises particles characterized by a volume-based distribution of equivalent spherical diameters determined by laser diffraction according to ISO 13320:2009, and the distribution exhibits

a Dv50 value in a range of 35 to 85 micrometers, wherein Dv50 is defined as the median equivalent spherical diameter;

a Dv01 value greater than 2 micrometers, wherein Dv01 is defined as the equivalent spherical diameter corresponding to 1 percent of the cumulative undersize distribution; and

a Dv99 value less than 115 micrometers, wherein Dv99 is defined as the equivalent spherical diameter corresponding to 99 percent of the cumulative undersize distribution.

2. The particulate material of claim 1 , wherein Z is a phosphorus atom.

3. The particulate material of claim 1 , wherein each occurrence of X is fluorine, c and d and e are zero, and b is an integer from 1 to 12.

4. The particulate material of claim 1 , wherein the sulfonate salt comprises tetra-n-butylphosphonium nonafluoro-n-butylsulfonate.

5. The particulate material of claim 1 , wherein the volume-based distribution of equivalent spherical diameters exhibits

a Dv10 value in a range of 30 to 50 micrometers, wherein Dv10 is defined as the equivalent spherical diameter corresponding to 10 percent of the cumulative undersize distribution, and

a Dv90 value in a range of 80 to 100 micrometers, wherein Dv90 is defined as the equivalent spherical diameter corresponding to 90 percent of the cumulative undersize distribution.

6. The particulate material of claim 1 , wherein the semicrystalline thermoplastic is a semicrystalline polycarbonate.

7. The particulate material of claim 1 , wherein the semicrystalline thermoplastic resin is a semicrystalline polyetherimide.

8. The particulate material of claim 1 , wherein

the semicrystalline thermoplastic is a semicrystalline polycarbonate; and

the sulfonate salt comprises tetra-n-butylphosphonium nonafluoro-n-butylsulfonate.

9. The particulate material of claim 1 , wherein

the semicrystalline thermoplastic is a semicrystalline polyetherimide; and

the sulfonate salt comprises tetra-n-butylphosphonium nonafluoro-n-butylsulfonate.

10. A method of powder bed fusion, comprising:

depositing a first layer comprising the particulate material of claim 1 at a working area;

irradiating the working area with first radiation effective to heat the first layer to a temperature below and within 10° C. of a melting onset temperature of the semicrystalline thermoplastic; and

selectively irradiating a portion of the working area with second radiation effective to heat the first layer to a temperature above a melting point of the semicrystalline thermoplastic.

11. The method of claim 10 , wherein the sulfonate salt comprises tetra-n-butylphosphonium nonafluoro-n-butylsulfonate.

12. The method of claim 10 ,

wherein the semicrystalline thermoplastic is a semicrystalline polycarbonate; and

wherein the sulfonate salt comprises tetra-n-butylphosphonium nonafluoro-n-butylsulfonate.

13. The method of claim 10 ,

wherein the semicrystalline thermoplastic is a semicrystalline polyetherimide; and

wherein the sulfonate salt comprises tetra-n-butylphosphonium nonafluoro-n-butylsulfonate.