Pulverulent composition, molding consisting thereof, process for producing a molding, and use of a pulverulent composition
A powdery composition contains at least one polyamide (PA) powder and is characterized in that the PA powder comprises a first polyamide (A) selected from the group consisting of PA5.9, PA5.10, PA5.11, PA5.12, PA5.13, PA5.14, PA6, PA6.66, PA6.9, PA6.10, PA10.9, PA10.10, PA10.12, PA10.13, PA12.9, copolymers and mixtures thereof, and the PA powder satisfies the following parameters: a melting point in the range of 180 to 240° C., a melt flow index of 400 cm 3 /10 min or less, measured at a temperature from 50 to 55° C. above the melting point, a melt flow index of 325 cm 3 /10 min or less, measured at a temperature from 30 to 35° C. above the melting point, and a melt flow index of 250 cm 3 /10 min or less, measured at a temperature from 10 to 15° C. above the melting point, each time measured at a test load of 5 kg. Additionally, the pulverulent composition has an elongation at break of at least 5.0% after sintering in a dry, untreated condition. The invention also relates to a molding that consists of such a pulverulent composition, a use of the pulverulent composition and a process for producing a molding.
1 . A method of using a powdery composition that includes
at least one powder made of a polyamide (PA), wherein:
the polyamide includes a first polyamide (A) that is selected from a group consisting of PA5.9, PA5.10, PA5.11, PA5.12, PA5.13, PA5.14, PA6, PA6.66, PA6.9, PA6.10, PA10.9, PA10.10, PA10.12, PA10.13, PA12.9, copolymers and mixtures thereof, and
wherein the PA powder includes the following parameters:
a melting temperature in the range of 180 to 240° C.,
a melt flow index of 400 cm 3 /10 min or less, measured at a temperature from 50 to 55° C. above the melting temperature,
a melt flow index of 325 cm 3 /10 min or less, measured at a temperature from 30 to 35° C. above the melting temperature, and
a melt flow index of 250 cm 3 /10 min or less, measured at a temperature from 10 to 15° C. above the melting temperature, each measured under a test load of 5 kg,
wherein the melt flow index is determined according to ISO 1133-1 and ISO 1133-2, with the PA powder to be tested being oven dried for at least 24 hours,
and in that, after sintering, the powdery composition in the dried, unconditioned state has an elongation at break of at least 5.0%, wherein the water content in the dry, unconditioned state is at most 0.2 weight percent, based on the total weight of the powdery composition after sintering, and the elongation at break is determined according to ISO 527-1,
in a production of a molded article that is made by a layer-by-layer process or by an additive manufacturing via selective sintering or fusing.
2 . The method of using powdery composition according to claim 1 , wherein the first polyamide (A) is selected from the group consisting of PA5.9, PA5.10, PA5.11, PA5.12, PA5.13, PA5.14, PA6, PA6.10, PA10.10, copolymers and mixtures thereof.
3 . The method of using powdery composition according to claim 1 , wherein the polyamide is a copolymer or a mixture of the first polyamide (A) and a second polyamide (B), with the second polyamide (B) selected from the group consisting of PA4.6, PA4.10, PA5.6, PA6.6, PA6.12, PA6-3-T, PAST, PAST, PA6T.6, PA12T, PA66.6, copolymers and mixtures thereof.
4 . The method of using powdery composition according to claim 1 , wherein the PA powder has a melt flow index of 240 cm 3 /10 min or less, measured at a temperature from 50 to 55° C. above the melting point,
of 160 cm 3 /10 min or less, measured at a temperature from 30 to 35° C. above the melting point, and
of 100 cm 3 /10 min or less, measured at a temperature from 10 to 15° C. above the melting point, each measured under a test load of 5 kg.
5 . The method of using powdery composition according to claim 1 , wherein after sintering, the powdery composition in the dried, unconditioned state has an elongation at break in the range of 5.0 to 100%.
6 . The method of using powdery composition according to claim 1 , wherein the powdery composition has one or more of the following parameters:
a particle size in the range of 0.1 to 200 μm,
a mean particle size D 50 in the range of 30 to 100 μm,
a bulk density of at least 330 g/L.
7 . The method of using powdery composition according to claim 1 , wherein the PA powder is present in a proportion of at least 55 weight percent, based on a total weight of the powdery composition.
8 . The method of using the powdery composition according to claim 1 , wherein the powdery composition comprises one or more of the following components:
an antioxidant in a proportion of 0.05 to 10 weight percent,
a flow additive in a proportion of 0.01 to 10 weight percent,
a lubricant in a proportion of 0.05 to 15 weight percent,
a dye in a proportion of 0.05 to 5 weight percent,
a filler in a proportion of 0 to 40 weight percent,
a flame retardant in a proportion of 0 to 40 weight percent, and
each based on a total weight of the powdery composition.
9 . The method of using the powdery composition according to claim 2 , wherein the first polyamide (A) is selected from the group consisting of PA6, PA10.10, copolymers and mixtures thereof.
10 . The method of using the powdery composition according to claim 6 , wherein the powdery composition has one or more of the following parameters:
a particle size in the range of 0.1 to 125 μm;
a mean particle size D 50 in the range of 40 to 90 μm,
a bulk density in the range of 350 to 750 g/L.
11 . The method of using the powdery composition according to claim 7 , wherein the PA powder is present in a proportion of at least 60 weight percent.
12 . The method of using the powdery composition according to claim 1 , wherein the powdery composition, after sintering, in the dried, unconditioned state has an elongation at break in a z-direction of at least 3.0% or more.