Powder and method for the preparation of three-dimensional objects

A powder for the preparation of three-dimensional objects comprising, or consisting of, supraparticles comprising

• at least a first population of first primary particles, wherein the first primary particles are thermoplastic polymeric particles,
• wherein the first primary particles have a volume-averaged median particle diameter (x50,3) of from 20 to 1000 nm,
• wherein the primary particles are agglomerated and/or partially sintered together to form the supraparticles;
• wherein the first primary particles have a spherical or at least approximately spherical shape, and
• at least a second population of second primary particles, whereby the second primary particles are selected from the group of organic particles, inorganic particles or combinations thereof,
• wherein the second primary particles have a volume-averaged median particle diameter (x50,3) of from 10 to 2000 nm,
• wherein the second primary particles are homogeneously distributed within the supraparticles, the second primary particles form a radial gradient within the supraparticles, the second primary particles are located in the core of the supraparticles or the second primary particles are located on the surface of the supraparticles;
• and
• wherein the second primary particles and the first primary particles are made of different materials;
• and
• wherein the supraparticles have a volume-averaged median diameter (x50,3) of from 4 to 60 μm,
• wherein the span of the particle size distribution of the supraparticles calculated according to the following formula
• span
• =
• x
• 90
• ,
• 3
• -
• x
• 1
• ⁢
• 0
• ,
• 3
• x
• 5
• ⁢
• 0
• ,
• 3
• (
• Eq
• .
• 2
• )
• is in the range of 0.7 to 2.5 and
• wherein the supraparticles have a spherical or at least approximately spherical shape, and
• wherein the supraparticles have a surface roughness of half the volume-averaged median particle diameter (x50,3) of the first primary particles and lower;
• or
• wherein the powder has a tensile strength of 20 Pa or less.