3D Printing Info

Filament comparison

e-TPU vs PVB

Compare printing settings, strength, heat resistance, dated prices and sources.

Foaming / expanded TPU (TPU Aero / TPU Air) guidePVB guide

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore PVB comparisons
e-TPU vs PVB — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXPVBSPECIALTY
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings$66.65/kg median; $49.32–$79.98/kg across 3 dated product listings
Identity & Market
Base polymer / chemistryFoaming thermoplastic polyurethane — a blowing agent expands the extrudate so the printed Shore hardness can be tuned by flow rate[1]Polyvinyl butyral — a printable thermoplastic whose surface can be smoothed with isopropyl alcohol instead of a hot solvent[2]
Densityg/cm³1.15 filament (Siraya Tech Flex TPU Air) and 1.05 (Roamr TPU Air HR), ISO 1183; the printed part falls to 0.51–0.93 depending on nozzle temperature (ISO 845)[3][4]1.10 (Polymaker PolySmooth, ISO 1183); Prusament PVB 1.10[2][5]
Typical priceUSD/kg1 kg-equivalent spools span 42–85; the middle of the market is about 52[6][7][8][9][10][11]1 kg-equivalent spools cluster near 80[12][13]
Price range across brandsUSD/kg42–85 across brands; QIDI TPU-Aero 42, Siraya Tech Flex TPU Air 45, Phaetus aeFlex TPU-Aero 49 direct and 40 at West3D, Roamr TPU Air HR 80A 55 at 800 g, Recreus Filaflex Foamy 73 at 750 g, colorFabb varioShore 85 at 700 g[6][7][8][9][10][11][14]49–102 across brands; Polymaker PolySmooth 49 at 750 g, Prusament PVB 80–102 at 500 g[12][13]
Market availability1–5Available from several mainstream brands — colorFabb, Recreus, QIDI, Phaetus, Siraya Tech and FusRock all sell an active-foaming TPU[1][6][7][8][10][11]Available from several mainstream brands[12][13]
Spool sizes & diameters1.75 mm; 0.7, 0.75, 0.8, 1 and 3 kg spools[1][6][8][9][11]1.75 and 2.85 mm; 0.5 and 0.75 kg spools[12][13]
Typical applicationsCushioning, midsoles, insoles and soft-touch parts where the softness needs to vary within one print; Siraya Tech's Roamr line is aimed specifically at printed footwear[1][9]Display models and light guides where a layer-free surface matters more than strength[2]
Diameter tolerance± mm0.03 (Siraya Tech and Roamr, 1.75 mm)[3][4]+/- 0.03 (Prusament PVB)[5]
Printing Parameters
Nozzle temperature°C230–270 (QIDI and Siraya Tech), 220–260 (Roamr); foaming activates near 230 °C and is strongest at the top of the range[1][3][4][10]215 +/- 10 (Prusament PVB)[5]
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[3][4][10]75 +/- 5 (Prusament PVB)[5]
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][4]Open frame is fine[2]
Part cooling fan100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[3][4]100 % part cooling (Prusament PVB)[5]
Bed surface & adhesion aidPEI sheet or painter's tape; Polymaker warns TPU can over-stick and advises a glue stick as a release agent, and Siraya Tech recommends PVP glue or Magigoo as a release agent on PEI[15][16][3]Smooth PEI sheet or satin sheet; Prusa states a brim is not generally necessary[5]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[8]Not documented
Stringing / oozing tendency1–5Severe — the material expands inside the hot end, so it oozes on travel moves; QIDI states retraction tuning cannot fix it and Siraya Tech advises setting retraction distance and speed to zero[3][10]Not documented
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[1]Easy — minor profile tuning; it prints close to PLA[2]
Extruder requirementDirect drive; the base material is a 92A TPU[1][17]Not documented
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[18][4]Brass fine indefinitely[2]
Abrasiveness1–5Non-abrasive[18]Non-abrasive[2]
Nozzle clog risk1–5Not documentedModerate — needs dry filament and a clean nozzle; Prusa calls PVB very prone to absorbing moisture and requires a 60 °C, 4 h dry before every print[19][20]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[15]Not documented
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[20]Very high (>2 %) — 2.36 % equilibrium water absorption (Polymaker PolySmooth), above every PLA and PETG grade here[2]
Equilibrium moisture content at ~50 % RH%1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[10]2.36 equilibrium water absorption (Polymaker PolySmooth); 2.09 for PolyCast; Prusament PVB takes up 0.18 in 24 h and 0.35 in 7 days at 24 °C and 22 % RH[2][21][5]
Drying temperature & time70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[3][4][10]Maximum 60 °C for 4-8 h depending on how wet the filament is (Prusament PVB)[5]
Symptoms when wetBubbling and popping at the nozzle, stringing and a rough surface; Siraya Tech adds that moisture wrecks the foaming itself, not only the surface[20][3]Not documented
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[20]Polymaker publishes no dry-versus-conditioned figures; at 2.36 % equilibrium uptake the material has to be kept dry to print cleanly[2][20]
Storage requirementSealed with desiccant; often kept in a dryer during the print[20]Sealed with desiccant[20]
Mechanical Properties
Tensile strength (XY)MPaFalls with foaming: colorFabb 24 unfoamed and 12 foamed (ISO 527-1A); Siraya Tech 10.3 at break printed at 240 °C down to 3.8 at 270 °C; QIDI 6.81 at break (ISO 527, XY)[1][3][10]51.8 ± 0.7 printed XY, ISO 527 (PolySmooth); 53.2 ± 1.1 for PolyCast; Prusament PVB gives 50 +/- 5 at yield printed horizontal (ISO 527-1) and 57 +/- 1 on the filament (ISO 527)[2][21][5]
Young's modulusMPa50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[1]2199 ± 43 printed XY and 2010 ± 69 printed Z, ISO 527 (PolySmooth); Prusament PVB gives 1700 +/- 100 in both print directions (ISO 527-1)[2][5]
Elongation at break%465 unfoamed and 450 foamed (colorFabb, ISO 527-1A); Siraya Tech 629 at 240 °C down to 475 at 270 °C; Roamr 760 down to 540; QIDI 576 (ISO 527, XY)[1][3][4][10]5.7 ± 0.5 printed XY, ISO 527 (PolyCast)[21]
Flexural strengthMPaNot documented72 +/- 1 printed horizontal and 73 +/- 3 printed vertical, ISO 178 (Prusament PVB)[5]
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[1]2233 ± 106 printed XY, ISO 178 (PolyCast); Prusament PVB gives 2200 +/- 100 horizontal and 2300 +/- 100 vertical (ISO 178)[21][5]
Charpy impact, notchedkJ/m²Not documented7 +/- 1 printed horizontal and 10 +/- 1 printed vertical, ISO 179-1 notched (Prusament PVB)[5]
Other impact dataNot documentedCharpy unnotched 55 +/- 7 printed horizontal and 59 +/- 12 printed vertical (Prusament PVB, ISO 179-1)[5]
Layer adhesion / Z tensileMPaNot documented26.3 ± 2.1 printed Z, ISO 527 (PolyCast); Prusament PVB gives 49 +/- 5 at yield printed vertical (ISO 527-1) and 9 +/- 1 on Prusa's interlayer adhesion test[21][5]
Brittleness1–5Very ductile — bends far before failing[1]Moderate[2]
Hardness (scale-specific)Shore A / Shore D / RockwellTunable by nozzle temperature: colorFabb 92 Shore A unfoamed; Siraya Tech 78 A printed at 240 °C falling to 63 A at 270 °C, Roamr TPU Air HR 80A 80 A down to 66 A and HR 85A 83 A down to 70 A (ISO 7619)[1][3][4][22]Shore D 77 (Prusa Polymers method)[5]
Creep resistance / sustained load1–5Poor — no foamed-grade creep test; a printed 95A TPU bar crept from 74.5 to 82.7 mm over 5 days at 1.25 kg[23]Not documented
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[16]Not documented
Elasticity / flexibility1–5Rubbery / highly elastic[1]Rigid[2]
Z strength as % of XY%Not documented98 (Prusament PVB, printed vertical against horizontal tensile yield, ISO 527-1: 49 +/- 5 against 50 +/- 5) — the most isotropic printed material in this dataset[5]
Thermal Properties
HDT at 0.45 MPa°CNot documented68 (PolySmooth) and 67 (PolyCast), ISO 75 at 0.45 MPa; Prusament PVB 63 (ISO 75 at 0.45 MPa)[2][21][5]
HDT at 1.8 MPa°CNot documented66 (PolySmooth) and 53 (PolyCast), ISO 75 at 1.8 MPa; Prusament PVB 58 (ISO 75 at 1.8 MPa)[2][21][5]
Glass transition (Tg)°CNot documented70 (DSC) for both PolySmooth and PolyCast[2][21]
Melting point / Vicat°CVicat softening drops as the foam expands: 83 printed at 240 °C to 53 at 270 °C (Siraya Tech, ISO 306); QIDI 70.4[3][10]Amorphous — no melting point; Vicat 70 (PolySmooth) and 67 (PolyCast), ISO 306[2][21]
Annealing responseFoaming activates near 230 °C and expands the extrudate about 1.6×; colorFabb advises dropping flow to 60–70 % to realise the weight saving, and Siraya Tech publishes a flow schedule from 85–90 % at 230 °C down to 50–55 % at 270 °C[1][3]Not documented
Environment & Chemical
UV resistance1–5Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[16]Not documented
Chemical resistanceWithstands industrial solvents and UV exposure (Polymaker)[16]Not documented
Food contactNot food safe without specific certification (Polymaker)[16]Not documented
Biodegradability / compostabilityNot biodegradable[16]Not documented
RecyclabilityNot accepted in household plastic collection[16]Not documented
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[24]Low hazard — minimal VOC and particle emission; none of these materials was in the chamber study[24]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[24]Open a window / occasional ventilation[24]
Post-Processing
Sanding & machiningDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[16]Not documented
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[16]Not documented
Vapour / chemical smoothingNo practical vapour smoothing[16]Isopropyl alcohol vapour smoothing is the point of the material — Polymaker markets PolySmooth for hands-free post-processing to a layer-free surface[2]
Support material pairingPolymaker warns TPU supports are often very difficult to remove[16]PolyDissolve S1 is rated for PVB (Polymaker)[25]
Dimensional accuracy & detailFoamed surfaces are matte and textured; holding a consistent hardness means holding the nozzle temperature steady, and the printed density moves by nearly a factor of two across the 230–270 °C window[1][3]PolyCast is the investment-casting variant of the same chemistry — it burns out cleanly rather than being smoothed[21]
Solvents & Solubility
Soluble inDMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[26]Isopropyl alcohol dissolves it; Prusa describes PVB as soluble only in IPA, and it is not water-soluble.[19]
Softened or crazed byToluene and benzene swell it up to +50 % by weight at 23 °C; the foamed wall soaks up esters and alcohols faster still.[26]Not documented
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[26]Isopropyl alcohol: brushed or sprayed on for speed, or several hours in IPA vapour for a glass-like surface.[27][19]

Material entries describe families or representative grades, not an interchangeable specification for every spool. Test methods, orientations and conditions may differ. Unknown values are marked “Not documented”. Prices and source dates remain historical snapshots; check the linked guide for product details. Differences highlight text, not a universal winner.

Sources for this comparison

  1. varioShore TPU Technical Data Sheet colorFabb · 2026-08 · tds
  2. PolySmooth Technical Data Sheet V5.4 Polymaker · 2024-11 · tds
  3. Siraya Tech Flex TPU Air Technical Data Sheet Siraya Tech · 2026-08 · tds
  4. Roamr TPU Air HR 80A Technical Data Sheet Siraya Tech · 2026-08 · tds
  5. Prusament PVB Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  6. Recreus product catalogue Recreus · 2026-08 · vendor
  7. varioShore TPU Natural — product page colorFabb US · 2026-08 · vendor
  8. Siraya Tech Flex TPU Air Black Filament — lightweight foaming flexible, product page Siraya Tech · 2026-08 · vendor
  9. Roamr TPU Air HR 80A Filament — product page Siraya Tech · 2026-08 · vendor
  10. TPU-Aero Lightweight TPU Filament — product page with specification tables QIDI Tech · 2026-08 · vendor
  11. aeFlex TPU-Aero — active foaming low weight TPU, product page Phaetus · 2026-08 · vendor
  12. Polymaker product catalogue Polymaker · 2026-08 · vendor
  13. Printed Solid product catalogue Printed Solid · 2026-08 · vendor
  14. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  15. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  16. TPU — material basics Polymaker Wiki · 2026-08 · doc
  17. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  18. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  19. Prusament PVB — material page Prusa Polymers · 2026-08 · tds
  20. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  21. PolyCast Technical Data Sheet V5.4 Polymaker · 2024-11 · tds
  22. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  23. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  24. Emissions of Ultrafine Particles and Volatile Organic Compounds from Commercially Available Desktop Three-Dimensional Printers with Multiple Filaments (Azimi et al.) Environmental Science & Technology 50(3) 1260-1268 · 2016-01 · paper
  25. PolyDissolve S1 Technical Data Sheet V5.4 Polymaker · 2024-11 · tds
  26. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  27. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc