Resin Data
TPV
Termoplástico Vulcanizado
TPV·Thermoplastic Elastomers·Amorphous
TPV (Thermoplastic Vulcanizate) is the only thermoplastic elastomer that approaches the performance of true vulcanized rubber —compression set 10-30% (same as a pressed EPDM), continuous HDT 125°C, exceptional chemical and UV resistance— while still being processable as a thermoplastic in 30-60 second injection cycles. The trick is chemical: during mixing, the EPDM (ethylene-propylene-diene rubber) component is dynamically vulcanized while dispersed in a continuous matrix of polypropylene (PP). The result is a "phase inversion": crosslinked rubber droplets micro-suspended in a sea of thermoplastic PP.
The absolute dominant brand is Santoprene (Celanese, ex-ExxonMobil, ex-Advanced Elastomer Systems, originally developed by Monsanto in 1981) —holding ~45% of the global TPV market. Alternatives: Teknor Apex Sarlink, Avient/SO.F.TER. Forprene, Zeon Zeotherm, Celanese Vyram.
Flagship applications: automotive weatherstrip seals (doors, windows, glazing, sunroof —replaced traditional EPDM in many OEMs because TPV enables 2K injection molding integrated with the plastic body), CV joint boots and rack-pinion boots (TPV flex-fatigue is among the best on the market), airbag covers, HVAC hoses, Santoprene MED medical tubing, premium comfort grips. Cost $3-7/kg —between TPO below and TPU/Pebax above. Are you running Santoprene? Share your experience with automotive seals 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) | 1.03:1 |
| L/D Ratio | 18 – 24 |
| Compression Ratio | 2.5 – 3.5 |
| Tonnage Factor | 3.86 – 5.41kN/cm² |
| Thermal Diffusivity | 0.1536mm²/s |
| Max Shear Rate | 20,0001/s |
| Shrinkage | 1.4 – 2.5% |
| Regrind | ❌ Not allowed |
| Heat Deflection (HDT) @ 1.82 MPa | 60°C |
| Glass Transition (Tg) @ 10°C/min | -51°C |
| Vicat Softening @ 50N | 102°C |
Drying
| Drying Temperature | 82 – 110°C |
| Drying Time | 2 – 4h |
| Recommended Moisture | 0.05% |
| Recommended Dryer Type | Air |
| Dew Point | -40°C |
Temperatures
| Melt | 193 – 232°C |
| Nozzle | 210 – 241°C |
| Front | 199 – 221°C |
| Middle | 193 – 216°C |
| Rear | 188 – 210°C |
| Demolding | 32 – 85°C |
| Mold (Cooling) | 16 – 74°C |
| Feed Throat | 35 – 79°C |
Processing
| Back Pressure | 3.4 – 9.7bar |
| Screw Speed | 100 – 200RPM |
| Injection Speed | High |
| Barrel Occupancy | 25 – 75% |
| Injection Pressure | 100 – 600Pbar |
| Holding Pressure | 25 – 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 | 0.76 – 6.35mm |
Venting
| Depth (Vent Depth) | 0.0203 – 0.1016mm |
| Land (Vent Land) | 0.762 – 1.52mm |
| Width (Vent / Clearance) | 4.06 – 12.7mm |
| Relief (Relief Channel) | 0.2032 – 0.4064mm |
Frequently asked questions
A **TPV** (Thermoplastic Vulcanizate) is a specific blend:
- **Matrix**: **polypropylene (PP)** —30-50% by weight, provides thermoplastic processability.
- **Dispersed phase**: **EPDM (ethylene-propylene-diene rubber)** —50-70% by weight— **dynamically vulcanized** during extruder mixing.
The "dynamically vulcanized" is the key: during **reactive extrusion**, a curative agent (peroxide, phenolic, silane) is added to the EPDM while it's being dispersed in molten PP. The EPDM forms **chemical crosslinks** within each microdroplet while remaining as **dispersed particles** (not as a continuous network —that would be a thermoset and couldn't be reprocessed).
Result: the material behaves **like vulcanized rubber** in use (low compression set, elastic recovery) but **like a thermoplastic** in process (melts, flows, recycles).
**45% of the global TPV market** is Santoprene. Five reasons why it replaced traditional EPDM in many automotive seals:
- **(1) 2K injection molding**: TPV can be **injected directly onto a rigid substrate** (PP, PC/ABS) in two-material operation (2K), creating a seal integrated with the plastic body —impossible with vulcanized EPDM.
- **(2) Complex geometry design**: weatherstrips with 3D profiles, injected corners that in EPDM required manual sticky-corner.
- **(3) Lower total cost**: 30-60s injection cycle vs 5-10 min EPDM vulcanization compensates for 2-3× higher material cost.
- **(4) Recyclable** (partially): production scrap reintegrable up to 15-25%, vs EPDM 0%.
- **(5) Compression set comparable** to EPDM —the seal doesn't "flatten" after 10 years of use.
Standard OEMs: Toyota, BMW, Mercedes-Benz, Ford, Honda use Santoprene in weatherstrips, glass run channels, body sealing systems.
- **TPO** ([Thermoplastic Polyolefin](/en/desktop/datos-de-resina/tpo)): mechanical PP + EPDM blend **without vulcanization**. EPDM dispersed without crosslinks. Result: **lower cost**, easier to process, **better paintability**, but **high compression set** (60-80%) —doesn't recover well after cyclic deformation.
- **TPV**: PP + EPDM **dynamically vulcanized**. EPDM crosslinked in microdomains. Result: **low compression set** (10-30%), **better continuous thermal resistance** (HDT 125°C vs TPO 80°C), **better chemical and UV resistance**, **more rubbery behavior**. Cost 50-100% higher than TPO.
**2026 rule of thumb**: **painted exterior bumper/fascia/panel** → **TPO**. **Seal/gasket/CV boot/cyclic deformation application** → **TPV**.
**Santoprene** (Celanese) has ~45% of the global market. Alternatives:
- **Teknor Apex Sarlink**: USA, second in North American market. Strong in automotive seals and consumer.
- **Avient (ex-SO.F.TER.) Forprene**: Italian, strong in EU. Soft-touch and medical grades.
- **Zeon Zeotherm**: Japan, specialized in oil-resistant and heat-resistant grades for under-hood.
- **Celanese Vyram**: Celanese's second brand, premium grades for 2K overmolding.
- **Mitsui Milastomer**: Japan, Asia-Pacific local alternative.
- **Wanhua, ELASTRON** (Turkey): emerging players in commodity grades.
**Historical curiosity**: Santoprene was developed by **Monsanto in 1981**, then passed to **Advanced Elastomer Systems** (Monsanto/ExxonMobil JV), then became 100% **ExxonMobil**, and since **2022** belongs to **Celanese** (in a $1.15 billion acquisition of ExxonMobil's elastomers business).
**Drying**: typically not required (PP and EPDM are non-hygroscopic). Some grades with color masterbatch or additives benefit from optional 80°C × 2-3h.
**Melt**: **175-230°C** (typical Santoprene: 200-220°C). Grades with lower compression set (more curative, more rigidity) run 220-230°C.
**Mold**: **20-60°C** —cold like other TPEs. Hot mold >70°C can affect cured EPDM balance.
**Injection speed**: high. TPV is **shear-dependent** —flows better at high speed because EPDM microdroplets orient and PP flows around them.
**Residence**: <10 min. Sustained >250°C starts degrading EPDM (generates burnt material, color shift).
**Screw**: **L/D 20-24, compression 2.0-2.5**. Generic PE screws (compression 3.0+) generate shear burn in TPV.
**Shore A 30 to Shore A 92** —covers the entire typical "rubber" range. For Shore D (semi-rigid), TPV isn't competitive —prefer rigid TPU or COPE/Hytrel.
Reference grades:
- **Santoprene 121-50** (Shore A 50): very soft, low-pressure seals, conformable gaskets.
- **Santoprene 101-64** (Shore A 64): medium, **standard automotive weatherstrips**.
- **Santoprene 121-73** (Shore A 73): medium-rigid, **CV joint boots**, comfort grips.
- **Santoprene 271-87** (Shore A 87): more rigid, **air ducts, structural seals**.
- **Santoprene 121-92** (Shore A 92): upper limit, **structural needing recovery**.
Higher Shore means less EPDM/more PP —more rigidity, less elastic recovery.
**Typical compression set: 10-30% at 22h in 25% strain, room temperature**. Under sustained pressure (a seal pressed against car door), TPV **doesn't "permanently flatten"** —when released, it recovers 70-90% of original height. After 10 years of continuous service, a TPV weatherstrip still seals.
**Comparison**:
- **Traditional vulcanized EPDM**: 10-20% compression set. **The gold standard**.
- **TPV (Santoprene)**: 10-30%. **Comparable, justifying the replacement**.
- **TPE-S (SEBS)**: 30-50%. Much worse.
- **Unvulcanized TPO**: 50-80%. Useless for critical seals.
- **TPU**: 30-50%. Good but not class A.
This is the **economic reason** Santoprene displaced EPDM in automotive —it approaches the gold standard of compression set while enabling process cycles 10× faster.
**Santoprene MED grades** (8000 series) are standard in:
- **Syringe plungers**: the piston seal in Luer-Lok syringes —Becton Dickinson, Terumo, Nipro use Santoprene MED.
- **Non-critical medical tubing**: drainage, collection, non-implant.
- **Vial stoppers** (in some grades): cap inserts.
- **Medical equipment gaskets** (partially autoclavable —max ~120°C, not 134°C extended).
- **Respirator components** (CPAP, ventilators) —soft-touch seals.
Meets **USP Class VI**, **ISO 10993** in MED grades. **Latex-free** (important post-2010 when natural latex allergies eliminated many materials). **DEHP/BPA-free** —natural replacement for FPVC in some disposables.
**Yes, but partially** —this is the difference vs pure thermoplastic TPEs. The dynamically vulcanized EPDM has chemical crosslinks that **don't break on remelting**, which limits recycling:
- **Post-industrial scrap (sprues, runners, rejects)**: reintegrable up to **15-25% regrind** without significant loss.
- **Post-consumer recycling**: very limited due to difficulty separating TPV from general plastic flow in municipal streams.
- **Closed-loop OEM programs**: Toyota, BMW recover internal scrap from weatherstrip manufacturing and reincorporate.
**Vs pure TPEs** (SEBS, TPU, TPO): recyclable up to 50%+. **Vs vulcanized EPDM**: completely non-recyclable. TPV is in the middle —**partially recyclable** and allows internal scrap recovery.
**Celanese Santoprene ECO-R** launched 2023 grades with up to 30% post-industrial recycled content without property loss.
**Two common issues**:
- **(1) Splay marks and poor surface finish** if **injection speed is too slow** —TPV requires high shear so EPDM microdroplets flow well with PP. **Cure**: increase velocity, open gates, use velocity-controlled injection profile (not pressure-controlled).
- **(2) Warpage in large parts** (1-3 m long weatherstrips) from **anisotropic shrinkage** —TPV with MD-oriented EPDM shrinks less in MD than TD, generating warpage. **Cure**: gate design with uniform flow path, stepped packing pressure, **post-mold cooling fixture** for critical weatherstrips.
Secondary issue: **2K overmolding adhesion** —if the substrate (PP, PC/ABS) isn't hot when the second TPV shot is injected, chemical adhesion is poor. **Cure**: manage the 2K cycle so first shot is at >100°C when second is injected, or use specific grades designed for adhesion to PC/ABS substrates (Santoprene 8281 series).
Sources
- Celanese — Santoprene TPV Thermoplastic Vulcanizates· Celanese
- ExxonMobil/Celanese — Santoprene Injection Molding Guidelines (PDF)· ExxonMobil / Celanese
- Celanese — Santoprene TPV Weatherseal Applications· Celanese
- Plastics Engineering — New Grades of Santoprene for Medical Tubing· Plastics Engineering
- Thermoplastic Vulcanizates (Wikipedia)· Wikipedia