3D Printing Info

Filament comparison

PPA vs TPU soft

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

PPA (polyphthalamide) guideSoft TPU (below 85A) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PPA comparisonsMore TPU soft comparisons
PPA vs TPU soft — documented properties and sources
PropertyPPA (polyphthalamide)PASoft TPU (below 85A)FLEX
Market snapshot
Listing priceUSD/kg; dated snapshots$45.49/kg median; $45.49–$45.49/kg across 1 dated product listings$114.04/kg median; $109.80–$122.27/kg across 4 dated product listings
Identity & Market
Base polymer / chemistryPolyphthalamide — a semi-aromatic polyamide in which aromatic diacid units replace part of the aliphatic backbone; Raise3D and Bambu Lab both label it high-temperature nylon[1][2]Very soft thermoplastic elastomers below 85 Shore A. Fiberlogy's FiberFlex 30D measures 81 Shore A, the softest grade with a published datasheet found here[3]
Densityg/cm³1.21 (ISO 1183, Siraya Tech Fibreheart PPA)[4]1.07 (Fiberlogy FiberFlex 30D, ISO 1183)[3]
Typical priceUSD/kgOne 1 kg listing on the market, at 45[5]1 kg-equivalent spools cluster near 115[6][7][8]
Price range across brandsUSD/kg45 for the only unfilled PPA filament found — Siraya Tech Fibreheart PPA at 1 kg; every other PPA in retail is carbon- or glass-filled[5]110–122 at 1 kg-equivalent; Recreus 70A 110 and 60A 116 at 500 g, NinjaTek Edge 83A 112, NinjaTek Chinchilla 75A 122; the Recreus 3 kg spools fall to 70–73[6][8][7]
Market availability1–5Special order, 1–2 makers worldwide — Siraya Tech is the only brand found selling unfilled PPA filament[5]Niche, a handful of specialist brands[3][9][6]
Spool sizes & diameters1.75 mm, 1 kg[5]1.75, 2.85 and 3 mm; 0.5, 0.85, 1, 2 and 3 kg spools[3][6][10][7]
Typical applicationsGears, bearings and tooling that must hold load above the reach of PA6 or PA12, and parts exposed to fuels and industrial chemicals[4]Highly compliant seals, soft grips and prosthetic liners[3]
Printing Parameters
Nozzle temperature°C280–300 (Siraya Tech)[4]Not documented
Bed temperature°C70–80 (Siraya Tech)[4]50–70 (Fiberlogy FiberFlex 30D)[3]
Enclosure / chamber requirement1–5Enclosure recommended — Siraya Tech advises an enclosure to hold temperature and limit warping on larger prints[4]Open frame is fine[3]
Part cooling fan20–60 % (Siraya Tech)[4]Not documented
Bed surface & adhesion aidPEI sheet with a glue stick, or a PVP glue coating[4]PEI sheet or painter's tape; Polymaker warns TPU can over-stick and advises a glue stick as a release agent[11][12]
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; needs a 300 °C-class hot end and a dry spool[4]Expert / industrial hardware only — below 85 Shore A the filament buckles in almost any feed path that is not a short, constrained direct drive[10][12]
Extruder requirementNot documentedDirect drive only, with a constrained filament path; Bowden is not viable at this hardness[10][9]
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Siraya Tech states a hardened steel nozzle is not needed for the unfilled grade[4]Brass fine indefinitely[13]
Abrasiveness1–5Non-abrasive when unfilled[4]Non-abrasive[13]
Nozzle clog risk1–5Moderate — needs dry filament and a clean nozzle; Siraya Tech tells users to dry only when moisture symptoms appear, rather than before every print[4]High — jams from moisture, heat creep or particles; below 85 Shore A the filament buckles and compresses, and Simplify3D warns that raised feed rates most likely end in a jam[11][12][14]
Heat-creep / jam sensitivity1–5Not documentedVery high — softens in the cold zone readily[12]
Hotend requirementHigh-quality metal nozzle, 0.4–1.0 mm; hardened steel not required (Siraya Tech)[4]No special hot-end required, but a direct-drive extruder is (Simplify3D)[11]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5High (0.8–2 %) — Siraya Tech publishes 2.59 % by ISO 62 immersion for the unfilled grade; on the equilibrium basis Bambu Lab uses, its 15 % carbon-filled PPA reaches 1.30 % against 2.35 % for the same maker's PA6-CF[4][2][15]Moderate[14]
Equilibrium moisture content at ~50 % RH%2.59 by ISO 62 water immersion (Siraya Tech, unfilled) — an immersion figure, not the 25 °C / 55 % RH equilibrium basis the filled grades are quoted on, so the two are not directly comparable[4]Not documented
Drying temperature & time80–100 °C for 4–6 h (Siraya Tech)[4]Not documented
Symptoms when wetOozing, bubbles and a rough surface finish (Siraya Tech)[4]Bubbling and popping at the nozzle, stringing and a rough surface[14]
Effect of moisture on strengthSiraya Tech publishes dry against saturated for the same grade: tensile 70 → 60 MPa, flexural 114 → 87 MPa, HDT at 1.8 MPa 73.5 → 48.5 °C, while Charpy rises 10 → 14.5 kJ/m²[4][5]Polymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[14]
Storage requirementDry box below 15 % RH (Siraya Tech)[4]Sealed with desiccant; often kept in a dryer during the print[14]
Mechanical Properties
Tensile strength (XY)MPa72 at break (printed, ASTM D638, Siraya Tech); the product page quotes 70 dry and 60 saturated[4][5]Not documented
Young's modulusMPa3600 (printed, ASTM D638, Siraya Tech)[4]Not documented
Elongation at break%10.5 at break (printed, ASTM D638, Siraya Tech)[4]870 at break (Fiberlogy FiberFlex 30D, ISO 527) — the highest elongation in the dataset[3]
Flexural strengthMPa115 (printed, ISO 178, Siraya Tech); 114 dry against 87 saturated on the product page[4][5]Not documented
Flexural modulusMPa3350 (printed, ISO 178, Siraya Tech)[4]Not documented
Charpy impact, notchedkJ/m²10.1 Charpy (printed, ISO 179, Siraya Tech); the data sheet does not state whether the specimen was notched[4]Not documented
Brittleness1–5Moderate — 10.5 % elongation at break puts it between PA6 and the fibre-filled grades[4]Very ductile — bends far before failing[3]
Hardness (scale-specific)Shore A / Shore D / RockwellNot documented81 Shore A and 30 Shore D (Fiberlogy FiberFlex 30D, ISO 7619)[3]
Creep resistance / sustained load1–5Good — Raise3D cites high creep resistance as a reason to choose the PPA matrix over other nylons[1]Poor — no creep test at this hardness; a printed 95A TPU bar crept from 74.5 to 82.7 mm over 5 days at 1.25 kg[16]
Fatigue / repeated-flex resistance1–5Not documentedExcellent — living hinges viable[12]
Elasticity / flexibility1–5Rigid — 3.6 GPa tensile modulus[4]Rubbery / highly elastic[3]
Wear resistance & frictionSiraya Tech describes the unfilled grade as low-friction and self-lubricating, aimed at gears and bearings[4][5]Tear strength 95 kN/m (Fiberlogy FiberFlex 30D, ISO 34-1)[3]
Thermal Properties
HDT at 0.45 MPa°C81 dry and 61 saturated (printed, ISO 75 Method B at 0.45 MPa, Siraya Tech)[4]Not documented
HDT at 1.8 MPa°C73.5 dry and 48.5 saturated (printed, ISO 75 Method A at 1.8 MPa, Siraya Tech) — unfilled PPA deflects near its Tg; the 190–227 °C figures quoted for PPA are carbon-filled grades[4][2]Not documented
Glass transition (Tg)°C80 (ASTM D3418, Siraya Tech)[4]Not documented
Melting point / Vicat°C231 melting point (ASTM D3418) and 230 Vicat (ISO 306), Siraya Tech[4]170 melting (Fiberlogy FiberFlex 30D, DSC)[3]
Annealing responseSiraya Tech's product page offers annealing for strength while its own data sheet says annealing is not recommended because the print can warp; on its 15 % carbon-filled PPA, annealing lifts HDT at 1.8 MPa from 82.5 to 119 °C[4][5][17]Not documented
Environment & Chemical
UV resistance1–5Not documentedGood — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[12]
Chemical resistanceWithstands fuels, oils and industrial chemicals; Bambu Lab rates semi-aromatic nylon better than general nylon against weak acids, weak alkalis and most organic solvents[4][2]Withstands industrial solvents and UV exposure (Polymaker)[12]
Water / humidity resistance in service1–5Absorbs water, properties shift — a saturated specimen loses about 15 % of its tensile strength and 25 °C of heat-deflection temperature[4][5]Not documented
Food contactNot documentedNot food safe without specific certification (Polymaker)[12]
Biodegradability / compostabilityNot documentedNot biodegradable[12]
RecyclabilityNot documentedNot accepted in household plastic collection[12]
Health & Safety
Fume toxicity1–5Not documentedLow hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[18]
Ventilation / filtration requirement1–5Not documentedOpen a window / occasional ventilation[18]
Post-Processing
Sanding & machiningNot documentedDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[12]
Gluing & solvent weldingNot documentedCyanoacrylate bonds TPU; no common solvent welds it[12]
Vapour / chemical smoothingNot documentedNo practical vapour smoothing[12]
Support material pairingCompatible with quick-release support materials (Siraya Tech)[4]Polymaker warns TPU supports are often very difficult to remove[12]
Solvents & Solubility
Soluble inDissolved at 23 °C by formic acid, phenol, m-cresol, 96 % sulphuric acid or hexafluoroisopropanol — all laboratory reagents.[19]DMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[20]
Softened or crazed byMineral acids, oxidants, halogens and zinc chloride solutions attack the amide bond; ordinary solvents do not.[19]Toluene and benzene swell it up to +50 % by weight at 23 °C; esters swell it severely; ethanol and IPA soften it.[20]
Solvent welding & smoothing agentNone — nylon's only solvents are formic acid, phenol and HFIP, all of which degrade the part they wet.[19]None practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[20]

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. Raise3D Industrial PPA CF Technical Data Sheet V2.0 Raise3D · 2022-04 · tds
  2. Bambu Filament Technical Data Sheet V1.0 — PPA-CF Bambu Lab · 2026-08 · tds
  3. FiberFlex 30D Technical Data Sheet Fiberlogy · 2026-08 · tds
  4. Siraya Tech Fibreheart PPA Technical Data Sheet Siraya Tech · 2026-08 · tds
  5. Siraya Tech Fibreheart PPA Filament — product page Siraya Tech · 2026-08 · vendor
  6. Recreus product catalogue Recreus · 2026-08 · vendor
  7. Chinchilla product page — print guidelines, spool sizes and price NinjaTek · 2026-08 · vendor
  8. NinjaFlex Edge product page — durometer, print guidelines and price NinjaTek · 2026-08 · vendor
  9. Filaflex 82A product page (Shore hardness and elongation) Recreus · 2026-08 · vendor
  10. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  11. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  12. TPU — material basics Polymaker Wiki · 2026-08 · doc
  13. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  14. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  15. Bambu Filament Technical Data Sheet V3.0 — PA6-CF Bambu Lab · 2026-08 · tds
  16. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  17. Siraya Tech Fibreheart PPA-CF Technical Data Sheet Siraya Tech · 2026-08 · tds
  18. 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
  19. Ultramid Nylon Chemical Resistance guide (unmodified PA6 B27E and PA66 A27E) BASF · 2026-08 · tds
  20. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds