PA 12 — Polyamide 12
Polyamide 12 is the standard material for compressed-air and hydraulic lines with demanding pressure and temperature requirements. Low moisture absorption, high dimensional stability, excellent resistance to oils, greases and fuels — and standard approval for compressed-air brake systems per DIN 73378.
Material at a Glance
Polyamide 12 (PA 12) is a semi-crystalline thermoplastic from the polyamide family. Compared to PA 6 and PA 6.6, PA 12 has the lowest moisture absorption of all technical polyamides — hence excellent dimensional stability even under changing humidity. Combined with high impact strength, low friction and good chemical resistance, PA 12 is the first choice whenever pressure, temperature and media contact are simultaneously demanding.
Strengths
- Very wide temperature range (−40 °C to +130 °C)
- Low water absorption → high dimensional stability
- Resistant to fuels, oils, greases, hydraulic fluids
- High pressure resistance, standard-approved for compressed-air brakes
- Low friction, well-suited for push-in fittings
Limitations
- UV resistance only in black colouring
- Sensitive to strong acids
- Not for food contact under pressure — choose PUR-L instead
- Higher material cost than LD-PE
PA 12-HL vs. PA 12-PHL — the two grades
Polyamide-12 tubes are split into two groups depending on plasticizer content — defined by DIN 73378. Both types are recyclable per EC guidelines.
Rigid
High-viscosity, low-plasticizer PA 12. Higher stiffness (tensile modulus ≈ 1500 MPa), higher pressure resistance. Ideal for compressed-air brakes at high pressures. Example: VESTAMID® L2140 NC.
Plasticized / flexible
Plasticized PA 12. Significantly more flexible (tensile modulus ≈ 400 MPa), smaller bend radius, easier routing. Especially for oil and petrochemical applications. Example: VESTAMID® L2124 NC.
Elastomer variant
Polyether block copolyamide based on PA 12 — plasticizer-free, high impact strength even at low temperatures, good hydrolysis resistance. Example: VESTAMID® E55-S3.
VESTAMID® Types Compared
Three VESTAMID® types from Evonik used for the extrusion of PA-12 tubes and hoses. Values from the original datasheets (Evonik Operations GmbH).
| Property | L2140 NC (HL) | L2124 NC (PHL) | E55-S3 (PEBA) |
|---|---|---|---|
| Type | PA 12-HL | PA 12-PHL | PA 12-Elastomer |
| Tensile modulus (dry) | 1500 MPa | 400 MPa | 215 MPa |
| Tensile strength (dry) | 44 MPa | 26 MPa | 38 MPa |
| Strain at break | 140 % | 200 % | 200 % |
| Shore D hardness | 75 | — | — |
| Melting temperature | 178 °C | 169 °C | — |
| Glass transition temp. | 45 °C | — | — |
| Density | 1,01 g/cm³ | 1,03 g/cm³ | — |
| Water absorption | 1,6 % | 1,3 % | — |
| Burning behaviour | HB | HB | HB |
| Standard compliance | DIN 73378 | DIN 73378 | — |
Type Profiles
VESTAMID® L2140 NC — rigid, high-strength
High-viscosity, heat- and light-stabilized PA 12 compound for the extrusion of compressed-air and fuel lines per DIN 73378 (type PA 12-HL). Tensile modulus of 1500 MPa and tensile strength of 44 MPa make it the first choice when maximum pressure resistance is required. Shore D 75.
VESTAMID® L2124 NC — flexible, plasticized
Plasticizer-modified, high-viscosity PA 12 with good dimensional control during tube extrusion (type PA 12-PHL). Tensile modulus of 400 MPa allows significantly smaller bending radii — specifically developed for oil and petrochemical applications as well as compressed-air lines where flexible routing is key.
VESTAMID® E55-S3 — PEBA elastomer
Thermoplastic elastomer based on PA 12 (polyether block copolyamide). Free from migrating plasticizers, no embrittlement or aging. Very good impact strength even at low temperatures, good hydrolysis resistance. Where PA 12-PHL is not flexible enough, E55-S3 bridges polyamide and PUR.
Typical Applications
Automotive — air brakes & fuel
Standard for compressed-air brake systems in trucks, buses and trailers (DIN 73378:1996-02 and DIN 74324-1:1996-02). Also for fuel and lubricant supply systems and vacuum lines. PA 12 is the only polymer class with serial approval in this safety domain.
Industrial pneumatics
Compressed-air lines in the low-pressure range, mini-hydraulics in measurement & control, lines for liquid and free-flowing substances. Vacuum-rated up to 12 × 9 mm. Drag-chain capable with careful design.
Chemistry & petrochemistry
Resistant to mineral oils, fuels, hydraulic fluids, many solvents and to alkalis and salt solutions. Low swelling, high dimensional stability even under varying humidity.
Pressure, Temperature & Standards
The permissible operating pressure of a PA-12 hose decreases with rising temperature. At +50 °C, typically only about 50 % of the +23 °C value remains, at +80 °C about 34 %. Detailed pressure utilisation tables are available on request.
Relevant Standards
| Standard | Scope |
|---|---|
| DIN 73378 | Polyamide tubes for motor vehicles — compressed-air brake systems, fuel and lubricant lines |
| DIN 74324-1 | Compressed-air brake systems — plastic compressed-air lines, dimensions and requirements |
Request PA 12 tube per DIN 73378
Rigid or plasticized, in 7 standard colours, as cut length, fixed length or on drum — we deliver the right specification.
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