3D-printed elastic products reinforced by means of continuous fibres and having asymmetrical elastic properties
The present invention relates to a fibre-reinforced 3D-printed elastic product (1, 3, 4, 7, 10, 12), wherein the product comprises a weight proportion of ≥50% of a polymer having a mean molecular weight of ≥5000 g/mol, measured by means of GPC, and a weight proportion of ≥0.5% and ≤20% of one or more fibres having an aspect ratio of ≥100 and a length of ≥3 cm and ≤1000 cm, the product being produced at least in part by means of an FFF (Fused Filament Fabrication) method, and the product having a tensile modulus of ≥1.5 GPa in the region of the fibre reinforcement and in the direction of the fibre symmetry axis. The product also has a tensile modulus, measured according to DIN EN ISO 527-1, of ≤1.2 GPa in the region of the fibre reinforcement and perpendicular to the fibre symmetry axis, and has a yield strength of >5%, measured according to DIN EN ISO 527-1, perpendicular to the fibre symmetry axis.
1. A fiber-reinforced, 3D-printed elastic product, comprising
a proportion by weight of ≥50% of a polymer having a number average molecular weight of ≥5000 g/mol, as measured by means of gel permeation chromatography, and
a proportion by weight of ≥0.5% and ≤20% of one or more fibers, the one or more fibers being a continuous fiber having an aspect ratio of ≥100 and a length of ≥10 cm and ≤1000 cm,
wherein the polymer comprises a thermoplastic elastomer,
wherein the product is at least partially produced by means of a Fused Filament Fabrication process,
wherein the product, in a region of fiber reinforcement and in a direction of a fiber symmetry axis, has a tensile modulus of ≥1.5 GPa as measured according to DIN EN ISO 527-1,
wherein the product, in the region of fiber reinforcement and perpendicular to the fiber symmetry axis, has a tensile modulus of ≤1.2 GPa as measured according to DIN EN ISO 527-1,
wherein the product, in the region of fiber reinforcement and perpendicular to the fiber symmetry axis, has a yield point of >5% as measured according to DIN EN ISO 527-1, and
wherein the thermoplastic elastomer is selected from the group consisting of thermoplastic copolyamides (TPA), thermoplastic copolyesters (TPC), olefin-based thermoplastic elastomers (TPO), styrene block copolymers (TPS), urethane-based thermoplastic elastomers (TPU), crosslinked olefin-based thermoplastic elastomers (TPV), polyvinyl chloride (PVC)-based thermoplastic elastomers, silicone-based thermoplastic elastomers, or a combination of at least two of these thermoplastic elastomers.
2. The product as claimed in claim 1 , wherein the product is rotationally symmetrical in at least one three-dimensional section and the fiber symmetry axis is aligned perpendicular to a product symmetry axis.
3. The product as claimed in claim 1 , wherein the product has an aspect ratio of ≥1 and the fiber symmetry axis lies essentially in a plane with a greatest product axis.
4. The product as claimed in claim 1 , wherein the product, in the region of fiber reinforcement, has a loss factor tan δ of ≤0.07 as measured by means of dynamic mechanical analysis in tensile loading, and a yield point in the direction of the fiber symmetry axis of <7% as measured according to DIN EN ISO 527-1.
5. The product as claimed in claim 1 , wherein the fibers comprise glass, carbon, basalt, polyester, polyethylene, polyurethane, polyamide, polyaramid, metal, or cellulose fibers, or mixtures of these.
6. The product as claimed in claim 1 , wherein a difference in the refractive index of the fibers and of the polymer is less than or equal to 0.1 and the polymer is a transparent polymer having a light transmission measured in a UV-VIS spectrometer on a sample having a thickness of 1 mm in a wavelength range of 400-800 nm of >50%.
7. The product as claimed in claim 1 , wherein a ratio between a length of a greatest product axis and an average of a fiber length is ≥0.5:1 to ≤10:1.
8. The product as claimed in claim 1 , wherein the product is a seal, a membrane, a drive belt, a pressure hose, an orthopedic prosthesis, an orthopedic aid, or a dental aligner.
9. The product as claimed in claim 1 , wherein the thermoplastic elastomer has a melting range of ≥20° C. to ≤280° C., as determined by differential scanning calorimetry, second heating at a heating rate of 20 K/min.
10. The product as claimed in claim 1 , wherein the thermoplastic elastomer has a Shore A hardness according to DIN ISO 7619-1 of ≥40 to ≤98.
11. The product as claimed in claim 1 , wherein the thermoplastic elastomer has a melt volume rate according to ISO 1133 of ≥5 to ≤200, measured 120° C. above the melting point, 10 kg.
12. The product as claimed in claim 1 , wherein the thermoplastic elastomer comprises a thermoplastic polyurethane elastomer.
13. The product as claimed in claim 12 , wherein the thermoplastic polyurethane elastomer is obtained from the reaction of the following components:
a) at least one organic diisocyanate;
b) at least one compound having groups reactive toward isocyanate groups and having a number-average molecular weight of ≥500 g/mol to ≤6000 g/mol and a number-average functionality of the sum total of the components b) of ≥1.8 to ≤2.5; and
c) at least one chain extender having a molecular weight of 60-450 g/mol and a number-average functionality of the sum total of the chain extenders c) of 1.8 to 2.5.
14. The product as claimed in claim 12 , wherein the thermoplastic polyurethane elastomer is obtained from the reaction of a polyisocyanate component and a polyol component, wherein the polyol component comprises a polyester polyol having a no-flow point (ASTM D5985) of ≥25° C.
15. The product as claimed in claim 1 , wherein the one or more fibers have the length less than 100 cm.