Resin Data
PEEK
Poliéter Éter Cetona
PEEK·High Performance·Semi-crystalline
PEEK (Polyether Ether Ketone) is the undisputed king of high-performance thermoplastics: the material with the best universal combination of thermal resistance (continuous use at 250°C), chemical resistance (attacked only by concentrated H₂SO₄), and mechanical strength (100 MPa tensile, 3.6 GPa modulus) among all plastics produced at scale. Developed by ICI (Imperial Chemical Industries) in the UK in the 1970s and commercialized in 1981 by Victrex —which still dominates the world market—, today the big three are Victrex, Solvay KetaSpire, and Evonik Vestakeep.
It's semi-crystalline, with melting point of 343°C and Tg of 143°C. Processes at melt 370-420°C, mold 160-190°C (hot mold mandatory for good crystallization), drying 150°C × 3 h. Carbon-fiber grades (CFR-PEEK) push modulus from 3.6 to 15+ GPa and HDT from 152°C to 327°C —they're the feedstock of aerospace brackets replacing aluminum and titanium, saving 40-60% in weight.
Dominant applications: aerospace (brackets, fasteners, wire insulation, oil & gas downhole tooling), medical implants (spinal cages, orthopedic fixations, dental abutments —PEEK's modulus is close to bone), premium automotive (bearings, seals). Flipside: extreme cost —$50-100/kg industrial, $200-400/kg medical implant grade. Are you running PEEK? Share your experience with hot molds and crystallinity 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 | Semi-crystalline |
| Specific Gravity (Density) | 1.3:1 |
| L/D Ratio | 16 – 24 |
| Compression Ratio | 2.5 – 3 |
| Tonnage Factor | 6.18 – 7.72kN/cm² |
| Thermal Diffusivity | 0.1131mm²/s |
| Max Shear Rate | 40,0001/s |
| Shrinkage | 1.2 – 1.6% |
| Regrind | ⚠ Caution |
| Heat Deflection (HDT) @ 1.82 MPa | 149°C |
| Glass Transition (Tg) @ 10°C/min | 143°C |
| Vicat Softening @ 50N | 250°C |
Drying
| Drying Temperature | 141 – 149°C |
| Drying Time | 2 – 6h |
| Recommended Moisture | 0.05% |
| Recommended Dryer Type | Desiccant |
| Dew Point | -40°C |
Temperatures
| Melt | 354 – 377°C |
| Nozzle | 360 – 399°C |
| Front | 379 – 410°C |
| Middle | 368 – 399°C |
| Rear | 349 – 379°C |
| Demolding | 116 – 213°C |
| Mold (Cooling) | 99 – 202°C |
| Feed Throat | 35 – 79°C |
Processing
| Back Pressure | 2.1 – 3.4bar |
| Screw Speed | 50 – 100RPM |
| Injection Speed | High |
| Barrel Occupancy | 25 – 75% |
| Injection Pressure | 700 – 1,400Pbar |
| Holding Pressure | 175 – 1,120Pbar |
| Cushion | 6.4 – 12.7mm |
Mold
| Runner Diameter | 3.05 – 6.1mm |
| Gate Diameter | 0.76 – 1.52mm |
| Gate Area | 0.46 – 1.82mm² |
| Wall Thickness | 0.51 – 3.05mm |
Venting
| Depth (Vent Depth) | 0.0203 – 0.0406mm |
| Land (Vent Land) | 0.508 – 1.02mm |
| Width (Vent / Clearance) | 3.05 – 7.62mm |
| Relief (Relief Channel) | 0.127 – 0.254mm |
Frequently asked questions
**PEEK** (Polyether Ether Ketone) is an aromatic **semi-crystalline** thermoplastic with chemical structure alternating ether (-O-) and ketone (-CO-) groups between phenyl rings. That molecular rigidity gives it: **Tm 343°C** (among the highest of commercial thermoplastics), **Tg 143°C**, **continuous use 250-260°C**, **near-universal chemical resistance**, **exceptional biocompatibility**, and **excellent fatigue and wear resistance**. It's the only thermoplastic combining metal-like properties (strength, temperature) with plastic advantages (weight, molding, no corrosion).
Three global producers dominate ~95% of the market:
- **Victrex** (UK, the pioneer, 1981) —the original "PEEK". Grades: Victrex PEEK 150G (standard), 450G (high viscosity), CA30 (30% CF), HMF (high modulus filler).
- **Solvay** (Belgium) — **KetaSpire** brand. Strong in medical and aerospace.
- **Evonik** (Germany) — **Vestakeep** brand. Leader in medical implant grade (Vestakeep i4 meets ASTM F2026 for permanent implants).
Secondary producers: **Gharda** (India), **Jilin Joinature, ZyPEEK** (China — scaling rapidly), **Drake Plastics** (USA, specialty machining).
- **Drying**: 150°C × 3-4 h in desiccant dryer (recommended 6 h for implant grades). Dew point <-40°C.
- **Melt**: 370-420°C. Some CF grades reach 430°C.
- **Mold**: **160-190°C mandatory** for optimal crystallinity (30-35%). If you mold with cold tool (<150°C), the part comes out amorphous and loses 30-50% of properties.
- **Residence**: <15-30 min (PEEK is thermally stable, one of its advantages).
- **Screw and barrel**: high-temperature steels, ideally with Ni-base or Stellite coating to resist CF-grade wear.
PEEK molded with hot mold reaches **30-35% crystallinity** —semi-crystalline phase with full properties: 100 MPa tensile, 152°C HDT, broad chemical resistance. If you mold with **cold mold** (<150°C), the part comes out **amorphous** (crystallinity <5%): loses rigidity (modulus drops 30%), HDT falls to ~145°C (just Tg), and becomes prone to stress-cracking in solvents. **Solution if cold mold is unavoidable**: do **post-mold annealing** at 200°C × 2-4 h to induce crystallinity. Not recommended for strict-tolerance parts because they shrink during annealing.
- **Structural brackets** replacing aluminum: 40-60% lighter, no galvanic corrosion with carbon composites dominating modern aircraft. Airbus A350, Boeing 787 use them extensively.
- **Wire insulation** and avionics connectors: PEEK doesn't propagate flame (V-0 inherent) and resists 250°C continuous —critical in engines.
- **Oil & gas downhole tooling**: valves, seals, connectors that must withstand 200°C+ and H₂S without degrading in deep wells.
- **Non-metallic engine components**: bearings, rotating seals, auxiliary parts in turbofan engines.
- **Non-metallic bushings and bearings** for flight control mechanisms.
Five unique reasons:
- **(1) Elastic modulus close to cortical bone** (3.6 GPa vs 18 GPa for bone vs 110 GPa for titanium). This **reduces stress-shielding** —when an implant is much stiffer than bone, bone loses density from disuse around the implant.
- **(2) Radiolucent** (X-ray transparent) —doctor can see bone underneath in post-op imaging, impossible with titanium.
- **(3) MRI-compatible** —no metallic artifacts.
- **(4) Biocompatibility meets ISO 10993** and ASTM F2026.
- **(5) Sterilizable** by gamma, EtO, and autoclave multiple cycles without degradation.
Flagship applications: **spinal cages** (intervertebral cages — largest market), **orthopedic fixations** (plates, screws), **dental abutments**, **personalized cranial prostheses**.
**Anisotropic and crystallinity-dependent**:
- **Unreinforced semi-crystalline** (with hot mold): 1.0-1.5% in flow direction, 1.5-2.0% transverse.
- **30% GF**: 0.3-0.6% MD, 0.8-1.2% TD.
- **30% CF**: 0.1-0.3% MD, 0.6-1.0% TD —very anisotropic due to fiber orientation.
- **Amorphous (cold mold)**: 0.5-0.8%, nearly isotropic, but with degraded properties.
Semi-crystalline PEEK's high shrinkage requires **careful oversize mold design** —not like reinforced PA where you offset 0.4%; with PEEK you think 1.2-1.5%.
The four high-performance engineering plastics —"super plastics" family:
- **PEEK**: best overall, semi-crystalline. Chemical, fatigue, temperature resistance. Highest cost.
- **PEI** ([Polyetherimide Ultem](/en/desktop/datos-de-resina/pei)): amorphous, transparent, HDT 200°C, medium cost. Aerospace interiors, high-frequency connectors.
- **PPS** ([Polyphenylene Sulfide](/en/desktop/datos-de-resina/pps)): semi-crystalline, HDT 260°C, excellent chemical resistance. Robust SMT connectors, automotive.
- **PPSU** ([Polyphenylsulfone](/en/desktop/datos-de-resina/ppsu)): amorphous, transparent, maximum hydrolysis resistance (sterilizable infinite times). Reusable medical.
**2026 rule**: maximum performance → PEEK. Amorphous performance + transparency → PEI. Automotive volume with good performance → PPS. Repeated sterilization + transparency → PPSU.
**Yes, mechanically and chemically**. Virgin PEEK + 25-50% regrind is routinely used in industrial grades without significant property loss —PEEK has **exceptional thermal stability**, withstands multiple extruder passes. **Implant-grade limitation**: regrind is not allowed (regulatorily). But **post-industrial recycled PEEK** is sold as intermediate grade at ~60% of virgin price, used in non-structural aerospace, oil & gas, technical industrial parts. Closed-loop programs at Airbus and Boeing recover structural PEEK machining scrap.
**$50-100/kg industrial**, **$200-400/kg implant grade**, vs $2 for PE. Reasons:
- **Expensive monomers**: 4,4'-difluorobenzophenone and hydroquinone are costly intermediates.
- **High-temperature polymerization** (340°C+) in diphenyl-sulfone solvent.
- **Low-volume production**: ~10-15 thousand tons/year globally (vs 110 million for PE).
- **High-value market**: 1 kg of PEEK replaces 3-5 kg of titanium in aerospace = huge ROI even if material is expensive.
**When is it worth it?**: when weight (aerospace), temperature (engines), or biocompatibility (medical) make the material **enabling**, not commodity. An aluminum bracket costs $5; the same in PEEK costs $50, **but saves 0.5 kg × 30 years of service × value of fuel saved in aviation** = pays back 10-20×.
Sources
- Victrex — PEEK Injection Molding: 5 Key Factors· Victrex
- Evonik — Vestakeep PEEK for Medical Applications (PDF)· Evonik
- PEEK (Polyether Ether Ketone) — Properties & Processing· SpecialChem
- Methods for Improving PEEK Bioactivity for Orthopedic & Dental Applications· NCBI / PMC
- Polyether Ether Ketone (Wikipedia)· Wikipedia