Powder compositions and methods of manufacturing articles therefrom
View Patent ↗Powder compositions and articles and methods of forming articles from powder compositions are provided. The powder compositions include at least one powder that preferably includes an amount of one or more branched polymers such as, for example, one or more branched polyamide polymers. The powder composition is preferably capable of being formed, via a layer-by-layer sintering process such as, for example, selective laser sintering, into a three-dimensional article.
1. A powder composition, comprising:
a laser-sinterable powder including at least 20 weight percent of a polyamide polymer component;
wherein the polyamide polymer component includes one or more branched polyamide polymers in an amount that comprises at least 5 weight percent of the laser-sinterable powder, wherein the branched polyamide comprises a star polymer having a single branching unit and at least 3 oligomer or polymer arms covalently attached to the branching unit, wherein the powder composition has a melt enthalpy of less than 100 j/g and a sintering window of less than 40° C.
2. The powder composition of claim 1 , wherein the single branching unit is attached to at least three branch units via amide linkages.
3. The powder composition of claim 1 , wherein the single branching unit is formed from a polycarboxylic acid.
4. The powder composition of claim 3 , wherein the polycarboxylic acid is chosen from benzene-pentacarboxylic acid; mellitic acid; 1,3,5,7-naphthalene-tetracarboxylic acid; 2,4,6-pyridine-tricarboxylic acid; pyromellitic acid; trimellitic acid; trimesic acid; 3,5,3′,5′-biphenyltetracarboxylic acid; 3,5,3′,5′-bipyridyltetracarboxylic acid; 3,5,3′,5′-benzophenonetetracarboxylic acid; 1,3,6,8-acridinetetracarboxylic acid; 1,2,4,5-benzenetetracarboxylic acid; anhydrides, amides, or esters thereof; or a mixture thereof.
5. The powder composition of claim 1 , wherein the single branching unit is formed from a polyamine.
6. The powder composition of claim 5 , wherein the polyamine is chosen from diethylenetriamine; triethylenetetramine; tris-(2-aminoethyl)amine; bis(hexamethylene)triamine; bis(6-aminohexyl)amine; 1,2,3-triaminopropane; 1,2,3,4-tetraaminobutane; melamine; a poly(propyleneoxide)amine based on trimethylolpropane or glycerin; a tallow triamine; or a mixture thereof.
7. The powder composition of claim 1 , wherein the single branching unit is formed from a polyamide.
8. The powder composition of claim 1 , wherein at least one of the oligomer or polymer arms comprises a reaction product of reactants including a C2-C20 amino acid, a C4-C20 lactam, or a mixture thereof.
9. The powder composition of claim 1 , wherein the branched polyamide includes a nylon-11 branch unit, a nylon-12 branch unit, or a combination thereof.
10. The powder composition of claim 1 , wherein the branched polyamide includes polyamide branch units formed from laurolactam, aminoundecanoic acid, or a mixture thereof.
11. The powder composition of claim 1 , wherein the branched polyamide includes polyamide branch units formed from a reaction product of reactants including aliphatic, cycloaliphatic, or aromatic C2-C36 diacids or C2-C36 diamines.
12. The powder composition of claim 1 , wherein the branched polyamide is a reaction product of one or more AB compound and one or more Bn compound, wherein:
A and B are functional groups capable of reacting with one another;
n denotes the number of B functional groups present in the Bn compound, and wherein n is 3 or more; and
the stoichiometry of the mole equivalents of Bn compound to mole equivalents of AB compound ranges from 0.0001:1 to 0.03:1.
13. The powder composition of claim 1 , wherein the branched polyamide comprises amine end groups.
14. The powder composition of claim 1 , wherein the branched polyamide comprises carboxylic acid end groups.
15. The powder composition of claim 1 , wherein the laser-sinterable powder comprises a ground powder.
16. The powder composition of claim 15 , wherein a test specimen exhibits an elongation at break of at least 3% when the powder composition is laser-sintered to form the test specimen.
17. The powder composition of claim 1 , wherein the powder composition has a melt enthalpy of 60 J/g to 70 J/g and wherein a volume-average particle diameter of the powder composition is between 5 and 100 microns.
18. A method, comprising:
providing a layer of the laser-sinterable powder of claim 1 ;
selectively melting at least a portion of the layer; and
forming a three-dimensional article by applying one or more additional layers to a preceding layer of the laser-sinterable powder.
19. The method of claim 18 , further comprising:
using residual powder composition from forming the three-dimensional article in a selective sintering process to produce a second three-dimensional article that does not exhibit orange peel.
20. A three-dimensional article comprising:
a plurality of sintered layers including a polymer matrix;
wherein the branched polyamide polymer of claim 1 forms at least 5 weight percent of the polymer matrix.