3D Printing Info

Filament comparison

e-TPU vs PP

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

Foaming / expanded TPU (TPU Aero / TPU Air) guidePolypropylene (PP) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore PP comparisons
e-TPU vs PP — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXPolypropylene (PP)POLYOLEFIN
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings$46.56/kg median; $31.99–$53.00/kg across 4 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]Polypropylene — a semi-crystalline polyolefin with no polar groups, so it neither absorbs water nor bonds to most bed surfaces[2][3]
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)[4][5]0.91 (Prusa PP composite, ISO 1183) — the lightest common filament[6]
Typical priceUSD/kg1 kg-equivalent spools span 42–85; the middle of the market is about 52[7][8][9][10][11][12]1 kg-equivalent spools span 27–53; the middle of the market is about 44[13][14][15][16]
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[7][8][9][10][11][12][17]27–53 across brands; Reli3D 32 on Amazon, SUNLU 44 at 0.8 kg, Fiberlogy 49 at 750 g, IEMAI 3D 53, and the 3DJake PP listing spans 27–49[13][18][14][15][16]
Market availability1–5Available from several mainstream brands — colorFabb, Recreus, QIDI, Phaetus, Siraya Tech and FusRock all sell an active-foaming TPU[1][7][8][9][11][12]Available from several mainstream brands[18][14][13]
Spool sizes & diameters1.75 mm; 0.7, 0.75, 0.8, 1 and 3 kg spools[1][7][9][10][12]1.75 and 2.85 mm; 0.75 kg spools are common[14]
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][10]Living hinges, chemical-resistant containers, automotive clips and packaging prototypes[2]
Diameter tolerance± mm0.03 (Siraya Tech and Roamr, 1.75 mm)[4][5]Not documented
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][4][5][11]210–230 (Braskem-type PE/PP window); Formfutura's Centaur PP melts at 205 ± 15 °C[2]
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[4][5][11]Not documented
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][5]Enclosure recommended — Simplify3D lists an enclosure as a hardware requirement and Polymaker advises one below 70 °C ambient to stop warping and cracking[19][3]
Part cooling fan100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[4][5]Part cooling fan required (Simplify3D)[19]
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[20][21][4]Packing tape, a polypropylene sheet, or a PP-specific adhesive such as Magigoo PP — ordinary PLA and ABS adhesives do not hold it[19][3]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[9]Not documented
Warping tendency1–5Not documentedHigh — enclosure needed for reliable large parts; PP's crystallinity drives shrinkage and Prusa recommends a brim on its PP grades[6][22]
Bed-adhesion difficulty1–5Not documentedVery difficult — special plates or slurry required. PP bonds to almost nothing; a polypropylene-specific tape or adhesive is the normal answer[6][3]
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[4][11]Slight — Polymaker advises 1–2 mm retraction at 20–30 mm/s[3]
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[1]Advanced — enclosure, hardware upgrades, tuning; bed adhesion is the whole problem[3][6]
Extruder requirementDirect drive; the base material is a 92A TPU[1][23]Not documented
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[24][5]Brass fine indefinitely for unfilled grades — Simplify3D states no special hotend is required[19]
Abrasiveness1–5Non-abrasive[24]Non-abrasive when unfilled[19]
Nozzle clog risk1–5Not documentedLow — Simplify3D lists no special hotend requirement for PP and clogging is not among its listed drawbacks[25][19]
Heat-creep / jam sensitivity1–5Not documentedSlightly sensitive[19]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[20]No special hot-end required (Simplify3D)[19]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[25]Negligible (<0.1 % EMC) — Prusa measures 0.03 % in 24 h and 0.04 % in 7 days on its PP composite, the lowest figures it publishes for any filament[6]
Equilibrium moisture content at ~50 % RH%1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[11]0.03 after 24 h and 0.04 after 7 days at 24 °C / 22 % RH (Prusa Polymers, measured on its PP composite)[6]
Drying temperature & time70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[4][5][11]No drying step is published for PP; uptake is below the level that affects printing[6]
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[25][4]Bubbling and popping at the nozzle; Polymaker still advises a 70 °C dry for 4–6 h despite the low uptake[3]
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[25]Not applicable in practice — with equilibrium uptake at 0.04 %, there is no moisture-driven strength loss to measure. Polymaker's sensitivity tiers put polyolefins below even PLA[6][25]
Storage requirementSealed with desiccant; often kept in a dryer during the print[25]No special storage needed[6]
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][4][11]12 at yield (Formfutura Centaur PP, ASTM D638)[2]
Young's modulusMPa50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[1]724 on extruded PP stock (ASTM D638; converted from 105,000 psi)[26]
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][4][5][11]Above 600 at break (Formfutura Centaur PP, ASTM D638)[2]
Flexural strengthMPaNot documented31.0 on extruded PP stock (ASTM D790; converted from 4500 psi)[26]
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[1]402 flexural modulus (Formfutura Centaur PP, ASTM D790) — an order of magnitude below any rigid filament[2]
Other impact dataNot documentedIzod notched 112 J/m on extruded PP stock, converted from 2.1 ft-lb/in (ASTM D256)[26]
Brittleness1–5Very ductile — bends far before failing[1]Very ductile — bends far before failing[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][4][5][27]Rockwell R102 (and M95) on extruded PP stock (ASTM D785)[26]
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[28]Below average[2]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[21]Excellent — living hinges viable, the classic polypropylene application[2]
Elasticity / flexibility1–5Rubbery / highly elastic[1]Semi-flexible[2]
Thermal Properties
HDT at 0.45 MPa°CNot documented74 on extruded PP stock (ASTM D648 at 66 psi; converted from 165 °F)[26]
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[4][11]205 ± 15 melting (Formfutura Centaur PP)[2]
Continuous service temperature°CNot documentedBounded by a melting point of 205 ± 15 °C and by the 158 °C heat deflection of the carbon-filled grade; no loaded-bar service figure is published for unfilled PP[2][6]
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][4]Not documented
Flammability / UL 94Not documentedFlammable; no UL 94 rating published for the grades surveyed[6]
Environment & Chemical
UV resistance1–5Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[21]Months outdoors before embrittlement — unstabilised polypropylene chalks under UV[3]
Chemical resistanceWithstands industrial solvents and UV exposure (Polymaker)[21]Excellent against acids, alkalis and most solvents — the usual reason to choose PP[3]
Water / humidity resistance in service1–5Not documentedExcellent — essentially unaffected[6]
Food contactNot food safe without specific certification (Polymaker)[21]Polypropylene is a common food-packaging polymer, but no filament here carries a food-contact certification[3]
Biodegradability / compostabilityNot biodegradable[21]Not biodegradable[3]
RecyclabilityNot accepted in household plastic collection[21]Mechanically recyclable as resin code 5, but printed waste is not accepted in household collection[3]
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[29]Low hazard — minimal VOC and particle emission. Inferred: no polyolefin was among the nine filaments in the Azimi chamber study, so this is a family-level judgement rather than a measurement[29]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[29]Open a window / occasional ventilation. Inferred — no polyolefin was measured in the chamber study[29]
Post-Processing
Sanding & machiningDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[21]Sands poorly — the waxy surface loads abrasive paper[19]
Painting & finishingNot documentedPaint and adhesives do not key to untreated PP; flame or plasma treatment is normally needed first[3]
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[21]Nothing common bonds untreated PP; flame or plasma treatment is needed before adhesives key[3]
Vapour / chemical smoothingNo practical vapour smoothing[21]No practical vapour smoothing[19]
Support material pairingPolymaker warns TPU supports are often very difficult to remove[21]Prints its own supports; no soluble support is rated for PP[19]
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][4]Shrinkage and warping dominate; the low modulus means parts flex rather than hold tolerance[6]
Solvents & Solubility
Soluble inDMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[30]None at room temperature; chloroform dissolves it at 60 °C and xylene at about 118 °C — the xylene-solubles route.[31][32]
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.[30]Xylene, decalin, CCl4 and chlorobenzene are heavily absorbed at 20 °C; oleum, chlorosulphonic acid and bromine destroy it.[31]
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[30]None — nothing softens PP at room temperature, so joints have to be welded thermally rather than chemically.[31]

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. Centaur PP Technical Data Sheet Formfutura · 2026-08 · tds
  3. PP — material basics Polymaker Wiki · 2026-08 · doc
  4. Siraya Tech Flex TPU Air Technical Data Sheet Siraya Tech · 2026-08 · tds
  5. Roamr TPU Air HR 80A Technical Data Sheet Siraya Tech · 2026-08 · tds
  6. Prusament PP Carbon Fiber Technical Datasheet v1.0 Prusa Polymers · 2024-11 · tds
  7. Recreus product catalogue Recreus · 2026-08 · vendor
  8. varioShore TPU Natural — product page colorFabb US · 2026-08 · vendor
  9. Siraya Tech Flex TPU Air Black Filament — lightweight foaming flexible, product page Siraya Tech · 2026-08 · vendor
  10. Roamr TPU Air HR 80A Filament — product page Siraya Tech · 2026-08 · vendor
  11. TPU-Aero Lightweight TPU Filament — product page with specification tables QIDI Tech · 2026-08 · vendor
  12. aeFlex TPU-Aero — active foaming low weight TPU, product page Phaetus · 2026-08 · vendor
  13. SUNLU product catalogue SUNLU · 2026-08 · vendor
  14. Fiberlogy PP Natural — product page 3DJake International · 2026-08 · vendor
  15. Reli3D Low Warp PP Filament 1.75 mm 1 kg Black — Amazon listing Amazon.com · 2026-08 · vendor
  16. IEMAI 3D PP 3D Printing Filament — store page IEMAI 3D · 2026-08 · vendor
  17. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  18. PP filament listing 3DJake International · 2026-08 · vendor
  19. Polypropylene — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  20. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  21. TPU — material basics Polymaker Wiki · 2026-08 · doc
  22. Prusament PP Glass Fiber Technical Datasheet v1.0 Prusa Polymers · 2024-11 · tds
  23. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  24. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  25. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  26. TECAFINE PP natural — stock shape properties Ensinger · 2026-08 · tds
  27. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  28. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  29. 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
  30. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  31. Pro-fax and Moplen polypropylene — Chemical Resistance Guide (20, 60 and 100 °C) LyondellBasell · 2026-08 · tds
  32. US 5,278,282 Polymer recycling by selective dissolution — xylene dissolution temperatures Nauman & Lynch, Rensselaer Polytechnic Institute · 1994-01 · paper