A structured summary for R&D engineers and manufacturing technologists: why the «longest» of the commodity polyamides barely drinks water, where this solves an engineering problem, and when it is worth paying for.
Definition
Polyamide 12 (PA12, designated PA12 under ISO 1043-1) is an aliphatic polyamide produced by ring-opening polymerization of laurolactam, a cyclic monomer with twelve carbon atoms. Hence the number in its name. Within the polyamide family, PA12 belongs to the so-called long-chain grades: between adjacent amide groups in its chain there are eleven methylene links, the most among commodity grades. It is precisely this feature that determines almost everything PA12 is valued for: one of the lowest water absorption values in the polyamide family, dimensional stability, and flexibility.
Chemistry and structure: why PA12 barely drinks water
Picture a chain in which the polar amide groups —CO—NH— are spaced like street lamps along a road. In polyamide 6 the lamps stand close together — every five carbon atoms. In PA12 they are sparse, every eleven. It is the amide groups that attract water molecules, so the lower their «density» in the chain, the less moisture the material takes up from air and water.
Hence the key figure. Whereas polyamide 6 absorbs about 9% moisture to saturation in water, PA12 typically absorbs only 1,3–1,5%. A difference of six to seven times directly means: a PA12 part swells far less, barely changes its dimensions or mechanical properties in a humid environment.
The flip side of that same coin: sparser amide groups mean weaker intermolecular interaction. That is why PA12 melts lower (around 178 °C versus 220 °C for PA6) and has a lower elastic modulus. This is not a «worse polyamide» — it is a different balance: less stiffness and heat resistance in exchange for stability, flexibility, and cold resistance.
Properties
The values below are typical for the class of unfilled PA12 in the dry state, not the data sheet of a specific grade. Verify exact parameters against the TDS and on trial molding.
| Parameter | Typical value | Method | Note |
|---|---|---|---|
| Density | 1,01–1,02 g/cm³ | ISO 1183 | lightest among commodity polyamides |
| Melting temperature | ≈178 °C | ISO 11357-3 | versus 220 °C for PA6, 260 °C for PA66 |
| Elastic modulus (dry) | 1,4–1,6 GPa | ISO 527 | CF/GF reinforcement raises it several-fold |
| Yield strength (dry) | 45–50 MPa | ISO 527 | ductile behaviour |
| Elongation at break | >200% | ISO 527 | ductile fracture |
| Water absorption, 24 h | ≈0,25% | ISO 62 | for PA6 — about 1,6% |
| Water absorption to saturation | 1,3–1,5% | ISO 62 | the key advantage of the class |
| Service temperature, continuous | roughly 80–90 °C | — | higher short-term; grade-dependent |
Its cold behaviour deserves a separate mention: PA12 typically retains impact strength and ductility at −40 °C, which is why it is used to make pneumatic tubing and fuel lines that work in winter under the hood and under the vehicle floor.
How it is manufactured
The industrial chain for PA12 is long and highly specialized. First, cyclododecatriene (CDT) is synthesized from butadiene, then through several stages it becomes laurolactam, which is finally ring-opening polymerized into PA12. Commercial production started in the late 1960s in Europe, and to this day the entire global volume is produced by a mere handful of companies — full-cycle producers can be counted on the fingers of one hand.
An unexpected turn: how a single explosion halted assembly lines around the world
The world learned just how narrow this «bottleneck» is on 31 March 2012, when an explosion and fire occurred at a cyclododecatriene plant in Marl, Germany. According to industry publications, roughly half of the world’s capacity for the key raw material for PA12 vanished from the market in one stroke. And since PA12 is used to make the fuel lines of most passenger cars, within a few weeks hundreds of automotive companies gathered at a crisis summit in Detroit: engineers urgently searched for a replacement material and checked how many weeks of stock remained in their warehouses. The assembly lines did not stop back then — but the industry long remembered that dependence on a single material with few producers is a strategic risk. For procurement, even today this is an argument for keeping a plan «B» behind PA12 — an agreed alternative polyamide or a second supplier.
Typical applications
- Automotive fuel systems. Multilayer fuel tubing — historically the main market for PA12: fuel resistance, flexibility, cold resistance.
- Pneumatics. Tubing for the brake and air systems of trucks: operation under pressure from −40 °C upward.
- Cable infrastructure. Protective cable jackets and conduit, including self-extinguishing UL94 V-0 grades.
- Marine and port engineering. Parts in constant contact with water, where PA6 «swells»: we wrote in detail about the selection logic in our article on carbon-filled PA12 for underwater drones.
- SLS 3D printing. Powdered PA12 is the most widely used material for selective laser sintering: it is used to print functional prototypes and small series.
- Sports and medicine. Ski-boot components, eyewear frames, catheter tubing — wherever flexibility and stability are required.
Comparison with its class neighbours
| Property (typical, dry state) | PA6 | PA66 | PA610 | PA12 |
|---|---|---|---|---|
| Melting temperature | 220 °C | 260 °C | ≈220 °C | 178 °C |
| Water absorption to saturation | ≈9% | ≈8% | ≈3,3% | 1,3–1,5% |
| Density | 1,14 | 1,14 | 1,08 | 1,01 |
| Elastic modulus | ≈3 GPa | ≈3,2 GPa | ≈2,1 GPa | 1,4–1,6 GPa |
| Behaviour at −40 °C | becomes brittle | becomes brittle | moderate | ductile |
| Approximate price level | 1× | 1,2–1,4× | 2–2,5× | 2,5–3× |
The selection logic is simple. If you need maximum stiffness and heat resistance at a reasonable price — look at PA66 versus PA6. If you need stability in water and in the cold — PA12 or, as a price compromise, PA610; among the niche long-chain grades PA612 and PA11, water absorption is comparable or even lower. And if the task is continuous operation at temperatures where aliphatic polyamides already give up, move to the polyphthalamide class: we covered it in a separate PPA guide.
Designation in industry
Under ISO 1043-1 the material is designated PA12; compounds — under ISO 1874: for example, «PA12-CF30» means 30% carbon fibre. Base grades for flammability have a UL94 HB class; for cable and electrical applications, halogen-free self-extinguishing formulations of class V-0 are produced. On drawings in the automotive and pneumatics industries you will often find additional requirements — plasticized (P) and light-stabilized (W) modifications.
PA12 in the Material Wizard range
MW maintains three PA12 lines — the base polymer, a carbon-filled compound, and a self-extinguishing compound for cable infrastructure. You can buy polyamide 12 with delivery across Ukraine from our warehouses in Derazhnia and Kharkiv; for the availability and price of a specific grade, check with a specialist.
Polyamide 12 (PA12)Base long-chain polyamideWater absorption to saturation 1,3–1,5% · Flexible · Cold-resistantRequest supply terms →For parts that require stiffness without losing PA12’s main advantage, the carbon-filled grade works — a carbon-nylon based on PA12. It is comparable to imported carbon-filled PA12 compounds, produced to our own formulation, and covers applications such as ATEX equipment and parts in contact with water.
Examid® PA12 CF30Carbon-filled PA12 (30% CF)Stability in a humid environment · ESD properties · ATEX applicationsRequest supply terms → Examid® PA12 E V0Self-extinguishing PA12 for extrusionUL94 V-0 · Hoses, conduit, cable jacketsRequest supply terms →A full overview of the class is on the long-chain polyamides page.
Limitations worth knowing in advance
PA12 is not a universal replacement for other polyamides. Without reinforcement its stiffness and heat resistance are noticeably lower than those of PA6/PA66: a modulus of 1,4–1,6 GPa and melting at 178 °C limit its use in hot zones. The price of the base polymer is typically 2,5–3 times higher than PA6 — paying for stability makes sense only where it is genuinely needed. Carbon-filled grades are abrasive to screws and hot runners and have anisotropic properties due to fibre orientation. And although PA12 absorbs little moisture, drying the pellets before processing is still required — it is simply faster than for PA6.
What to check before a production run
- Pellet moisture before molding/extrusion and the actual drying regime.
- Dimensional and geometric stability of the part after conditioning and «wet–dry» cycles.
- Impact strength on the actual part at the minimum service temperature (for example, −40 °C).
- Ageing in contact with the working medium: fuel, oils, seawater.
- For CF grades — wear of the mould, screw, and hot runner, and the behaviour of weld lines.
- Batch-to-batch consistency of characteristics and behaviour after reprocessing of scrap.
Expert breakdown: 5 questions worth asking before choosing PA12
1. Does the part really work in a humid or cold environment? If not — PA6/PA66 may well be enough, and the premium for PA12 is not justified.
2. What is the real maximum temperature of the assembly? Continuously above ~90 °C — be careful: look at PA66, PA610, or the PPA class, not PA12.
3. Is the stiffness needed from the material or from the geometry? Often a stiffening rib is cheaper than switching to a reinforced compound; if not — PA12 CF30 gives a several-fold increase in modulus.
4. Are there flammability requirements in the specification? Base PA12 is HB; for cable applications, budget for a self-extinguishing V-0 grade from the outset, rather than «we’ll sort it out later».
5. What is the plan «B» for raw material? The lesson of 2012: for critical PA12 parts it is worth agreeing an alternative grade or a second supplier in advance.
FAQ
How does PA12 differ from PA6 in simple terms?
PA12 takes up six to seven times less water, is more dimensionally stable, more flexible, and works in the cold, but melts lower, is less stiff, and is more expensive. PA6 is an all-rounder at the best price, PA12 is a specialist for moisture and cold.
Is it true that PA12 is nylon?
Yes, in everyday speech the entire polyamide family is still called nylon. The technically correct name is polyamide 12: twelve carbon atoms in the monomer unit.
What is the water absorption of PA12?
Typically about 0,25% over 24 hours and 1,3–1,5% to saturation in water — the lowest values among commodity polyamides. For comparison: PA6 absorbs about 9% to saturation.
Where is PA12 used most often?
Fuel and pneumatic tubing for vehicles, protective cable jackets, parts in contact with water, powders for SLS 3D printing, sports equipment.
Can PA12 be bought in Ukraine?
Yes. Material Wizard supplies base PA12, carbon-filled Examid® PA12 CF30, and self-extinguishing Examid® PA12 E V0 from warehouses in Derazhnia and Kharkiv — you can buy with delivery across Ukraine after checking availability with a specialist.
Material Wizard — a Ukrainian supplier of engineering polymers: technical material selection, samples for testing, warehouses in Derazhnia and Kharkiv.