Resin Data
TPU
Poliuretano Termoplástico
TPU·Thermoplastic Elastomers·Amorphous
TPU (Thermoplastic Polyurethane) is the "Swiss Army knife" of thermoplastic elastomers: the widest hardness range (Shore A 60 to Shore D 80), the best abrasion resistance among all TPEs, and one of the few materials combining rubber-like properties with oil resistance, transparency, and conventional thermoplastic processing. It's a block copolymer with hard segment (urethane formed by isocyanate + chain extender) and soft segment (polyol —polyester or polyether).
Key sub-classification: ester-TPU (Elastollan C series, Estane) offers better abrasion, tensile, and oil resistance but hydrolyzes in continuous hot water; ether-TPU (Elastollan 1400) is hydrolysis-resistant and low-temperature flexible, ideal for outdoor and wet environments. Global brands: BASF Elastollan (world leader), Covestro Desmopan (ex-Bayer, strong in medical), Lubrizol Estane (the original, patented in 1959), Wanhua Wanthane (China leader), Huntsman Irogran.
Flagship applications: athletic and safety footwear soles (Adidas Boost uses revolutionary expanded ETPU), transparent smartphone cases (anti-yellowing grades critical), hydraulic and pneumatic hoses, abrasion-resistant cable jacketing, rigid medical catheters, automotive airbag covers. Processing-wise: mandatory drying 80-110°C × 3-6h (the most hygroscopic of TPEs), melt 180-220°C, mold 20-40°C. Cost $5-15/kg. Are you running TPU? Share your experience 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 Structure | Amorphous |
| Specific Gravity (Density) | 0.95:1 |
| L/D Ratio | 18 – 24 |
| Compression Ratio | 2.5 – 3.5 |
| Tonnage Factor | 3.86 – 5.41kN/cm² |
| Thermal Diffusivity | 0.2105mm²/s |
| Max Shear Rate | 20,0001/s |
| Shrinkage | 0.1 – 1.2% |
| Regrind | ⚠ Caution |
| Heat Deflection (HDT) @ 1.82 MPa | 77°C |
| Glass Transition (Tg) @ 10°C/min | -46°C |
| Vicat Softening @ 50N | 88°C |
Drying
| Drying Temperature | 71 – 96°C |
| Drying Time | 2 – 4h |
| Recommended Moisture | 0.05% |
| Recommended Dryer Type | Desiccant |
| Dew Point | -40°C |
Temperatures
| Melt | 216 – 229°C |
| Nozzle | 179 – 218°C |
| Front | 179 – 218°C |
| Middle | 171 – 213°C |
| Rear | 166 – 204°C |
| Demolding | 43 – 57°C |
| Mold (Cooling) | 27 – 46°C |
| Feed Throat | 35 – 79°C |
Processing
| Back Pressure | 3.4 – 6.9bar |
| Screw Speed | 40 – 75RPM |
| Injection Speed | Low |
| Barrel Occupancy | 40 – 75% |
| Injection Pressure | 200 – 600Pbar |
| Holding Pressure | 50 – 480Pbar |
| Cushion | 5.1 – 12.7mm |
Mold
| Runner Diameter | 4.06 – 7.11mm |
| Gate Diameter | 1.02 – 1.52mm |
| Gate Area | 0.81 – 1.82mm² |
| Wall Thickness | 0.51 – 4.57mm |
Venting
| Depth (Vent Depth) | 0.0203 – 0.0305mm |
| Land (Vent Land) | 0.508 – 1.02mm |
| Width (Vent / Clearance) | 3.05 – 10.2mm |
| Relief (Relief Channel) | 0.127 – 0.254mm |
Frequently asked questions
**TPU** (Thermoplastic Polyurethane) is a **block copolymer** with two alternating components:
- **Hard segment** (~10-30% by weight): formed by reaction of **diisocyanate** (MDI, TDI or HDI) with a **chain extender** (typically 1,4-butanediol). Hard segments aggregate forming "crystalline domains" acting as physical crosslinks —providing rigidity, temperature, strength.
- **Soft segment** (~70-90% by weight): formed by a **polyol** —can be polyester (polyester polyol) or polyether (polyether polyol). The polyol provides elasticity, flex-fatigue, energy return.
Unlike thermoset PU (foams, memory foam), TPU **has no permanent chemical crosslinks** —physical domains "break" on heating, enabling thermoplastic processing.
The choice of **polyol** defines TPU's character:
- **Ester-TPU (polyester-based)**: better **tensile strength**, **abrasion resistance**, **oil/fuel resistance**, higher temperature. **Critical limitation**: **hydrolysis in continuous hot water** —ester bonds break slowly in H₂O >60°C, failing within years of service. Applications: safety soles, hydraulic hoses, industrial cable jacketing.
- **Ether-TPU (polyether-based)**: **excellent hydrolysis resistance** (years in hot water without degradation), **better low-temp flexibility** (-40°C+), **microbial resistance** (doesn't support fungal growth in humidity). Limitation: lower abrasion. Applications: medical catheters, outdoor equipment, screen protectors, smartphone cases.
**2026 rule**: outdoor/wet/medical → **ether**. Industrial/oil/abrasion → **ester**.
Five producers dominate ~85% of the global market:
- **BASF Elastollan** (Germany) — **world leader**. C series (ester), 500/600 (premium ester), 1100/1200 (ether), 1400 series (high-performance ether launched 2024).
- **Covestro Desmopan** (Germany, ex-Bayer Material Science) — strong in **medical and automotive**. Desmopan Rx medical grade.
- **Lubrizol Estane** (USA) — **the original TPU**, patented 1959 by BF Goodrich. Leader in US medical and industrial grades.
- **Wanhua Wanthane** (China) — **Asia volume leader**, scaling rapidly in commodity grades.
- **Huntsman Irogran**, **Avient Versollan**, **Merquinsa Pearlthane** — secondary players.
**Drying is critical** (TPU is the most hygroscopic of TPEs):
- **Shore A 60-85** (soft): 80-90°C × 6 hours.
- **Shore A 85+** and **Shore D**: 100-110°C × 3-5 hours.
- Final moisture <0.05%. Dew point <-30°C in desiccant dryer.
**Melt**: 180-220°C (depends on Shore — soft 180-200°C, rigid 200-220°C).
**Mold**: 20-40°C (cold like other TPEs).
**Residence**: <8 min. TPU degrades fast if it stays in the barrel —purge with PE/PP at shift end.
**Injection speed**: medium. Excessive shear generates burnt material.
**Adidas Boost** (launched 2013 in collaboration with BASF) uses **ETPU** (expanded TPU) instead of traditional EVA foams. Differences:
- **>90% energy return** (vs 60-65% EVA) due to **individually expanded TPU microspheres** —each "boost" is a TPU sphere blown with supercritical CO₂, fused with neighbors in mold thermofixing process.
- **Thermal stability**: ETPU doesn't compact with heat (vs EVA which loses response in hot climates).
- **Infinite flex-fatigue**: the shoe maintains response for 500-1000 km of running.
Applications: **Adidas Ultraboost, Yeezy Boost 350/700**, Solar Boost, Pulseboost. **Nike** responded with ZoomX (expanded PEBA —see [TPA](/en/desktop/datos-de-resina/tpa)). The **premium running shoe market 2026** divides between these two camps.
Five combined reasons:
- **(1) Optical transparency** (specific grades): to show phone logo and design.
- **(2) Shock absorption** Shore A 80-90: protects from drops without adding much bulk.
- **(3) Soft-touch grip** that doesn't slip.
- **(4) Resistance to sweat, oil, alcohol** (hands, hand sanitizer).
- **(5) Anti-yellowing grades** specific (Wanhua Wanthane CA, BASF Elastollan SP) with UV stabilizers so the case doesn't yellow in 6 months.
**Premium brands**: Spigen, OtterBox, UAG, Mous use TPU (often combined with PC in the back and TPU in edges for shock absorption).
**Limitation**: TPU **always yellows eventually** —anti-yellow grades extend useful life to 1-2 years, but no TPU is 100% color-stable indefinitely.
- **TPU wins on**: **abrasion resistance**, **tensile strength**, **cost** (~30-50% of LSR), **processing in conventional thermoplastic machine** (no dedicated equipment), **superior transparency**, **wider Shore range** (A60-D80).
- **LSR wins on**: **temperature** (continuous use 200°C+ vs TPU 90-110°C), **implantable biocompatibility**, **low-temp** (-50°C without hardening), **very low compression set**, **infinite UV-stable transparency**.
**2026 rule**: for **consumer overmolding, smartphone cases, footwear, cables** → **TPU**. For **implantable medical, high-temp parts, microfluidics** → **LSR**.
**Varies by Shore and formulation**:
- **Soft TPU Shore A 70-85**: 1.0-2.0% (higher, more elastomer).
- **Medium TPU Shore A 85-95**: 0.7-1.3%.
- **Rigid TPU Shore D 50-75**: 0.5-1.0%.
Anisotropy is moderate (0.1-0.3% MD vs TD difference). TPU is semi-crystalline with low crystallinity (~10-20%), so shrinkage is predictable but **post-mold dimensional stability** depends heavily on cooling —recommended **annealing 1-2h at 80°C** for parts with strict tolerances (luers, medical connectors, cellphone cases with click-fit).
**Biocompatible ether-TPU** is standard in:
- **Rigid catheter shafts**: where Pebax is too soft, rigid TPU (Shore D 55-75) offers more push strength. Estane 5800 series, Desmopan Rx.
- **Drainage, gastrostomy, foley catheters**: soft TPU Shore A 70-90, conforms anatomically without hardening.
- **Hospital bracelets** (Estane, Wanthane CL): patient identification.
- **Wound dressings and breathable films** (TPU films with selective water vapor permeability).
- **Non-DEHP IV tubing**: replacement for DEHP-FPVC in European MDR.
- **Cardiac assist devices**: special blood-contact biocompatible TPUs (Carbothane, Pellethane —Lubrizol).
Compliance: USP Class VI, ISO 10993, EtO and gamma sterilizable. **Not steam-autoclavable at 134°C** (TPU loses properties) —prefer Pebax or PEEK if repeated autoclave is required.
**Insufficient drying** —TPU is the most hygroscopic of the TPE family and polyether-based absorbs **0.5-1%** moisture in ambient air in 24h. If you process with moisture >0.05%, **defects guaranteed**:
- **Bubbles and silver streaks** in injected parts.
- **Hydrolysis** of soft segment during processing → molecular weight drop → brittle parts months later.
- **Splay marks** on surface.
**Cure**: mandatory drying 80-110°C × 3-6h (by Shore), desiccant dryer with dew point <-30°C, **don't open bag more than 1h before loading**, tropical climates require in-line drying or desiccant bags.
Second issue: **screw size mismatch** —soft TPU (Shore A <85) requires **low-compression screw (1.5-2.0 ratio)** and slow screw speed to avoid shear burn. Generic PE screw with 3.0+ compression degrades soft TPU rapidly.