Polyketone powder for laser sintering
In one instance a semicrystalline polyketone powder useful for additive manufacturing is comprised of a bimodal melt peak determined by an initial differential scanning calorimetry (DSC) scan at 20° C./min and a D 90 particle size of at most 300 micrometers and average particle size of 1 micrometer to 150 micrometers equivalent spherical diameter. In another instance, A composition is comprised of a semicrystalline polyketone powder having a melt peak and a recrystallization peak, wherein the melt peak and recrystallization peak fail to overlap.
1. A composition comprising an aliphatic semicrystalline polyketone powder comprising a mixture of a first aliphatic semicrystalline polyketone powder having a bimodal melt peak determined by an initial differential scanning calorimetry (DSC) scan at 20° C./min and a second aliphatic semicrystalline polyketone powder having a monomodal melt peak determined the DSC scan at 20° C./min and the aliphatic semicrystalline polyketone powder having a D 90 particle size of at most 300 micrometers and D50 particle size of 10 micrometers to 125 micrometers equivalent spherical diameter, wherein the semicrystalline polyketone powder is a copolymer of ethylene, carbon monoxide and at least one other alkene monomer.
2. The composition of claim 1 , wherein the semicrystalline polyketone powder is a copolymer of ethylene, carbon monoxide and at least one other alkene monomer that is an olefin.
3. The composition of claim 2 , wherein the other alkene monomer is an olefin having 3 to 12 carbons.
4. The composition of claim 2 , wherein the ethylene is present in a ratio of ethylene/other alkene of about 2 to 100.
5. The composition of claim 1 , wherein the first aliphatic semicrystalline polyketone powder has a recrystallization peak that overlaps a portion of the bimodal melt peak during the initial heating and cooling DSC scan.
6. The composition of claim 5 , wherein upon a subsequent DSC scan, the first aliphatic semicrystalline polyketone powder has a monomodal melt peak.
7. The composition of claim 6 , wherein the subsequent DSC scan has a recrystallization peak that overlaps a portion of the monomodal melt peak.
8. The composition of claim 1 , wherein the polyketone powder has a detectable amount of a group 8-10 transition metal catalyst.
9. The composition of claim 1 , wherein the melt peak has a melt enthalpy of at least 5 joules/gram of polyketone powder.
10. A composition comprised of an aliphatic semicrystalline polyketone powder having a melt peak and a recrystallization peak as determined by differential scanning calorimetry (DSC) scanned at a 20° C./min heating and cooling rate and a D 90 particle size of at most 300 micrometers and D50 particle size of 10 micrometers to 125 micrometers equivalent spherical diameter, wherein the melt peak is monomodal and the melt peak and recrystallization peak fail to overlap, wherein the semicrystalline polyketone powder is a copolymer of ethylene, carbon monoxide and at least one other alkene monomer.
11. The composition of claim 10 , wherein the melt peak has a melt peak onset temperature and the recrystallization peak has an onset recrystallization temperature that are at least separated by 10° C.
12. The composition of claim 10 , wherein the semicrystalline polyketone powder is a copolymer of ethylene, carbon monoxide and at least one other alkene monomer that is an olefin.
13. The composition of claim 12 , wherein the other alkene monomer is an olefin having 3 to 12 carbons.
14. The composition of claim 12 , wherein the ethylene is present in a ratio of ethylene to the other alkene in a ratio of about 2 to 100 by weight.
15. A method for forming an aliphatic polyketone powder useful for making an additive manufactured article comprising:
(i) reacting carbon monoxide, alkene monomer in the presence of a group 8 through 10 transition metal catalyst to form a raw polyketone powder,
(ii) recovering the raw polyketone powder, and
(iii) separating the raw polyketone powder to form the polyketone powder having a D 90 particle size of at most 300 micrometers and D 50 particle size of 10 micrometer to 125 micrometers equivalent spherical diameter and an oversized polyketone powder, wherein the aliphatic polyketone powder is a copolymer of ethylene, carbon monoxide and at least one other alkene monomer and has a bimodal melt peak determined by an initial differential scanning calorimetry (DSC) scan at 20° C./min, wherein the polyketone powder, raw polyketone powder or oversized polyketone powder is subjected to conditions further crystallizing said polyketone powder.
16. The method of claim 15 , wherein the further crystallizing is comprised of heat treating any one of the said polyketone powders to a temperature with 50° C. below its peak melt temperature as determined by DSC for a time to increase the crystallinity forming an increased crystallinity polyketone.
17. The method of claim 16 , wherein the increased crystallinity polyketone has a melt peak onset temperature and a recrystallization onset temperature that are at least separated by 10° C.