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Resin Data
TPA

Poliamida Termoplástica Elastómera

TPA·Thermoplastic Elastomers·Amorphous

TPA (Thermoplastic Polyamide Elastomer, also known as PEBA — Polyether Block Amide) is the material that changed marathon running in 2016, when Nike launched the Vaporfly with PEBA foam and carbon plate and runners started systematically breaking records. It's a block copolymer alternating rigid polyamide segments (PA) with flexible polyether segments —the first gives it rigidity and thermal resistance, the second elasticity and energy return.

The dominant world brand is Arkema Pebax (since 1981, practically synonymous with TPA). Alternatives: Evonik Vestamid E, EMS-Chemie Grilamid TR, Ube (Japan). Its great property: high energy return with low hysteresis —stretches, relaxes, returns >80% of energy. Combined with very low density (~1.01 g/cm³, almost floats), Shore D 25-72 range, exceptional flex-fatigue, and use from -40°C to +120°C, it defines the premium material for elite athletic footwear.

Flagship applications: midsole foams in running shoes (Nike Vaporfly/Alphafly, Adidas Adios Pro, Saucony Endorphin, ASICS Metaspeed —all PEBA), plates and insoles for sports, ski boot shells, interventional medical catheters (Pebax MED Class VI). Processing-wise: drying 80°C × 4-6h, melt 220-260°C, cold mold 20-40°C, wide processing window. Cost $15-30/kg. Are you running Pebax? Share your experience with energy return and footwear in the comments.

The ranges shown in these data tables were compiled by the MVPS team from various parameter sheets and literature, integrating the lower and upper limits for each material type.

This information must be carefully reviewed when developing injection molding processes. Final ranges and processing tolerances are the responsibility of the engineer in charge.

These ranges are not recommended for developing specific process tolerances. MVPS always recommends requesting and consulting the supplier's data sheet.

General Properties

Chemical StructureAmorphous
Specific Gravity (Density)1.02:1
L/D Ratio18 – 24
Compression Ratio2.5 – 3.5
Tonnage Factor3.86 – 5.41kN/cm²
Thermal Diffusivity0.1473mm²/s
Max Shear Rate20,0001/s
Shrinkage0.3 – 1.4%
Regrind⚠ Caution
Heat Deflection (HDT) @ 1.82 MPa52°C
Glass Transition (Tg) @ 10°C/min-70°C
Vicat Softening @ 50N110°C

Drying

Drying Temperature66 – 74°C
Drying Time4 – 6h
Recommended Moisture0.04%
Recommended Dryer TypeDesiccant
Dew Point-40°C

Temperatures

Melt152 – 199°C
Nozzle143 – 199°C
Front143 – 199°C
Middle138 – 193°C
Rear138 – 193°C
Demolding41 – 71°C
Mold (Cooling)24 – 60°C
Feed Throat35 – 79°C

Processing

Back Pressure3.4 – 6.9bar
Screw Speed40 – 80RPM
Injection SpeedMedium
Barrel Occupancy25 – 75%
Injection Pressure150 – 800Pbar
Holding Pressure38 – 640Pbar
Cushion5.1 – 12.7mm

Mold

Runner Diameter4.06 – 7.11mm
Gate Diameter1.02 – 1.52mm
Gate Area0.81 – 1.82mm²
Wall Thickness0.51 – 3.05mm

Venting

Depth (Vent Depth)0.0203 – 0.0406mm
Land (Vent Land)0.508 – 1.02mm
Width (Vent / Clearance)3.05 – 10.2mm
Relief (Relief Channel)0.127 – 0.254mm

Frequently asked questions

**TPA** (Thermoplastic Polyamide Elastomer) or **PEBA** (Polyether Block Amide) is a **block copolymer** —not a mechanical blend— that alternates in the same polymer chain: - **Hard polyamide segments** (typically PA12 or PA6, ~30-70% by weight) acting as crystalline "anchors" providing rigidity, temperature, resistance. - **Soft polyether segments** (PEG, PTMG) providing elasticity, flex-fatigue, energy return. By varying the proportion and type of each block, Arkema (the original firm) produces **the entire Shore D 25-72 hardness range** —from a very soft elastomer to a semi-rigid plastic— **without needing plasticizers**. This differentiates it from FPVC (which requires phthalates or DOTP) and from TPU (another block copolymer, urethane-based).
The **Nike Vaporfly 4%** —launched in 2016— combined for the first time: - **Expanded PEBA foam** (blown Pebax foam) in the midsole, giving **>80% energy return** vs ~60-65% of traditional EVA. - **Curved carbon plate** under the foam, acting as a spring/lever. Independent studies (Hoogkamer 2018, Barnes & Kilding 2019) confirmed **4% improvement in running energy cost** —translating to **2-3 minutes less in a marathon** for a sub-3h runner. Since then, **all marathon world records** (Kipchoge 2:01:09 Berlin 2022, etc.) are run with PEBA+carbon shoes. Adidas, Saucony, ASICS, Hoka —all premium brands launched equivalent versions.
Pebax nomenclature is logical: the first two digits of the name indicate **approximate Shore D hardness**: - **Pebax 2533** (Shore D ~25): very soft, **running midsole foams**, seals. - **Pebax 3533** (Shore D ~33): soft-medium, comfort foams, catheter tips. - **Pebax 4033/5033** (Shore D 40-50): medium, **flexible catheters**, medical tubing. - **Pebax 6333/7033** (Shore D 63-70): semi-rigid, **shoe plates**, **rigid catheter shafts**, ski boot instep. - **Pebax 7233** (Shore D 72): very rigid, technical parts needing some elasticity without losing structure. The **"MED"** suffixes (Pebax 6333 SA 01 MED) indicate medical Class VI grade; **"Renew"** indicates biobased version with sugarcane.
- **Drying**: 80°C × 4-6 h in desiccant dryer. Final moisture <0.05%. Hygroscopic (PA component). - **Melt**: 220-260°C (depends on grade — softer 220-240°C, more rigid 240-260°C). - **Mold**: **20-40°C** —cold compared to engineering plastics, because chains need to cool fast to avoid excessive crystallization of the PA block. - **Residence**: <8 min. Pebax is thermally stable but sustained >280°C starts degrading. - **Injection speed**: high. Good flow —enables **very thin walls (0.8 mm)** and complex geometries.
Pebax MED is **the #1 material for interventional cardiology/urology catheters**: - **Catheter shafts** with **variable stiffness**: the doctor needs rigidity at the proximal end (for pushing) and flexibility at the distal end (for navigating arteries). Achieved by extruding PEBA of **different Shore D** along the catheter. - **Ultra-flexible catheter tips** to avoid tissue damage. - **Angioplasty balloons** (some). - **Flexible drainage and infusion tubing**. Unique advantages: **Class VI biocompatible**, **consistent flexibility at body temperature** (37°C) without hardening, **very low hysteresis** (doesn't remain deformed), **excellent elastic memory**, **EtO and gamma sterilizable**.
Both are high-performance TPE (Thermoplastic Elastomers): - **TPA/Pebax wins on**: **lower density** (~1.01 vs 1.20 for TPU), **infinite flex-fatigue** (doesn't break with millions of cycles), **better low-temp flexibility** (maintains elasticity at -40°C), **higher energy return**. - **TPU** ([Thermoplastic Polyurethane](/en/desktop/datos-de-resina/tpu)) **wins on**: **abrasion resistance** (better than PEBA for soles with wear), **tensile strength**, **lower cost** (~30% cheaper), oil resistance. **2026 rule**: for **midsole, energy return, low-temp performance, catheters** → **Pebax/PEBA**. For **shoe outsoles, protective equipment, industrial hoses** → **TPU**.
**Moderate anisotropic**: - **Soft grades (Shore D 25-40)**: 1.5-2.5% MD, 1.5-2.5% TD —nearly isotropic. - **Medium grades (Shore D 40-60)**: 1.0-2.0%. - **Rigid grades (Shore D 60-72)**: 0.8-1.5%. Shrinkage is high as in other PA-based semi-crystallines. For precision technical parts (catheter parts, sport plates), oversize mold design mandatory. Expanded PEBA foams (footwear midsoles) have even higher shrinkage (3-5%) from the blowing agent.
**Yes, mechanically**, up to 20-25% regrind in industrial grades. **Thermally stable**, PA and polyether segments retain structure. **Limitation for medical**: regrind not allowed. **For footwear**: there are pilot programs from Nike, Adidas, and others that collect used shoes and recover PEBA, but **separation from carbon plates and other components** is complex —less than 5% of footwear PEBA is currently recycled. **Pebax Renew** (biobased) offers the alternative of **sugarcane as feedstock** (~50% biocontent), reducing footprint without changing properties.
Three combined properties: - **(1) Low hysteresis**: when you deform it (footstrike), polyether chains stretch like springs but **don't dissipate energy as heat**. They return to shape giving back almost all stored energy. - **(2) Very low density**: the midsole weighs less, less energy consumed lifting the foot. - **(3) Infinite flex-fatigue**: a shoe lasts 500-800 km (millions of strikes) without material losing properties —vs EVA which compacts and loses response in 200-300 km. The combination of **PEBA foam + curved carbon** is the technology defining elite footwear 2026, replicated by all premium brands.
**Insufficient drying** —Pebax is hygroscopic due to PA component, and if you process wet (>0.05%) **it hydrolyzes during processing**, losing molecular weight. Symptoms: **bubbles, silver streaks, elongation loss, color shift**. Cure: 80°C × 4-6h drying mandatory without shortcuts, **don't open bag more than 1h before loading**, tropical climates require in-line drying. Second issue: **variable shrinkage between grades** —changing from Pebax 6333 to 5533 implies **re-measuring the mold** because shrinkage changes 0.5%+. For multi-cavity catheter tooling, **qualify each grade in each cavity** before production.

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