Polyamide 11 (PA11)

Material Profile: Polyamide 11 (PA11) for Selective Laser Sintering

SLS Engineering Material Technical Report Series

Compiled from manufacturer technical datasheets and peer-reviewed literature

Abstract—Polyamide 11 (PA11, Nylon 11, EOS PA 1101) is a 100 % bio-based semi-crystalline polyamide derived from castor oil (Ricinus communis) via 11-aminoundecanoic acid. Among SLS thermoplastics it occupies the 'high-ductility / impact-resistant' niche complementary to PA12: PA11 parts achieve elongation at break ≈ 45 % and Charpy notched impact ≈ 8 kJ/m² (about 2× PA12), at the cost of slightly lower modulus. Because of its superior toughness PA11 is preferred for living-hinge and snap-fit components, automotive crash-relevant interiors, and impact-protection equipment. The renewable feedstock gives PA11 a substantially lower cradle-to-gate carbon footprint than petrol-derived PA12; EOS markets a carbon-offset 'PA 1101 ClimateNeutral' grade. This profile summarises composition, anisotropic mechanical behavior, recommended SLS parameters, thermal limits, and representative applications.

Index Terms—additive manufacturing, selective laser sintering, SLS, polyamide 11, PA11, PA 1101, nylon 11, bio-based polymer, castor oil.

I.  MATERIAL IDENTIFICATION

This section establishes the canonical names and commercial designations under which the material is supplied.

A.  Designation

Trade names: EOS PA 1101 (white) / PA 1102 (black) / PA 1101 ClimateNeutral; BASF Ultrasint PA11 (Black / Black CF / ESD); Arkema Rilsan Invent / Rilsan PA11 powder; HP 3D PA 11. All grades share the bio-based PA11 backbone; differences are color additives, refresh-ratio tuning, and certification packages.

B.  Full Chemical Name

Polyamide 11, poly(11-aminoundecanoic acid) or poly(undecanamide). It is a semi-crystalline aliphatic polyamide produced by polycondensation of 11-aminoundecanoic acid, which is in turn synthesised from castor oil (a renewable triglyceride). The repeat unit contains a single amide group spaced by 10 methylene units.

C.  Aliases and Alternative Designations

II.  COMPOSITION AND MOLECULAR STRUCTURE

A.  Empirical Chemical Formula

Repeat unit: -[NH-(CH₂)₁₀-CO]-_n. Empirical formula of the repeat unit: C₁₁H₂₁NO. Bio-based content per ASTM D6866 carbon-14 method: ≈ 100 % (vs 0 % for petrol-derived PA12).

Fig. 1.  Repeating unit / structural schematic of the polymer matrix.

Fig. 2.  Schematic of the single-phase polymer (no reinforcement).

B.  Composition Breakdown

TABLE I
 COMPOSITIONAL BREAKDOWN OF PA11 (NYLON 11, EOS PA 1101) (TYPICAL / PER SUPPLIER DATASHEET)

III.  MECHANICAL PROPERTIES — XY BUILD DIRECTION (HORIZONTAL)

In the XY orientation the tensile load is applied parallel to the powder-bed plane (in-plane). For polymer SLS this is typically the stronger orientation due to better neck formation between particles within a single layer; for metal DMLS/SLM, columnar β / α-grain growth perpendicular to the build direction also yields different anisotropy that is partially relieved by post-build heat treatment (e.g. stress-relief, HIP).

TABLE II
 MECHANICAL PROPERTIES — XY ORIENTATION (PA11 (NYLON 11, EOS PA 1101))

IV.  MECHANICAL PROPERTIES — Z BUILD DIRECTION (VERTICAL)

In the Z orientation the tensile load is applied perpendicular to the powder layers; failure occurs across inter-layer fusion bonds. For polymer SLS the Z properties are typically 70–90 % of XY; for metal LPBF (laser powder-bed fusion) processes Z elongation is often higher due to the columnar grain structure but UTS / yield can be slightly lower in the as-built state. Heat treatment (anneal, HIP) reduces the anisotropy substantially.

TABLE III
 MECHANICAL PROPERTIES — Z ORIENTATION (PA11 (NYLON 11, EOS PA 1101))

PA11 exhibits the lowest XY-vs-Z anisotropy of any commercial SLS thermoplastic — the EOS PA 1101 datasheet reports identical UTS and modulus in X / Y / Z directions, with Z-direction elongation at break of 30 % (vs 45 % XY). The exceptional inter-layer bond is attributed to the lower melt viscosity of PA11 vs PA12, which improves chain inter-diffusion across the layer interface during the transient melt window.

V.  RECOMMENDED PROCESS PARAMETERS

Values summarised below give consensus operating windows from public datasheets (EOS, 3D Systems, BASF Forward AM, SLM Solutions). Specific machines and parameter sets may differ within ±10 %; the supplier's verified parameter sheet always supersedes this table.

TABLE IV
 RECOMMENDED LASER POWDER-BED-FUSION PROCESS PARAMETERS FOR PA11 (NYLON 11, EOS PA 1101)

VI.  GLASS TRANSITION TEMPERATURE (TG)

Reported / typical Tg: ≈ 46 °C.

Tg slightly higher than PA12 (~41 °C). The EOS PA 1101 datasheet reports HDT @ 0.45 MPa of 180 °C and HDT @ 1.80 MPa of 46 °C — the 0.45 MPa value is unusually high because of PA11's high crystallinity (~25 %) and 201 °C melting point.

VII.  HEAT DEFLECTION TEMPERATURE (HDT)

Heat deflection temperature is the temperature at which a standard bar deflects 0.25 mm under a specified flexural load (ASTM D648 / ISO 75).

TABLE V
 HEAT DEFLECTION TEMPERATURE OF PA11 (NYLON 11, EOS PA 1101) UNDER STANDARD TEST LOADS

VIII.  DISTINGUISHING CHARACTERISTICS AND STANDARDS

A.  Bio-based feedstock & carbon footprint

PA11 is produced from castor oil (Ricinus communis), a non-food-crop oilseed grown principally in India and Brazil. Cradle-to-gate CO₂e is approximately 50 % lower than petrol-derived PA12. EOS offers PA 1101 ClimateNeutral, a carbon-offset variant verified to a recognised offset standard.

B.  Outstanding ductility and impact resistance

Elongation at break ≈ 45 % (vs ≈ 18 % for PA12), Charpy notched ≈ 8 kJ/m² (vs ≈ 4.4 for PA12), and Z-direction elongation ≈ 30 %. These properties make PA11 the SLS polymer of choice when parts must absorb impact energy without fragmenting — for example, automotive crash-zone interior components must by regulation not splinter on impact.

C.  Chemical resistance

PA11 inherits the broad chemical resistance of the polyamide family: excellent against hydrocarbons, fuels, oils, ketones, aldehydes, mineral bases and salts. Slightly less resistant than PA12 to polar solvents (alcohols, water) due to higher amide density per repeat unit.

D.  Biocompatibility (Cytotoxicity)

EOS PA 1101 is certified to ISO 10993-5 cytotoxicity, supporting use in skin-contact and short-term implant accessory applications. It is not certified for long-term implants — for which medical-grade PEEK or DMLS Ti6Al4V remain the references.

E.  Lower anisotropy

Among commercial SLS polymers, PA11 has the smallest XY-vs-Z difference. This makes it preferred for parts whose critical loads are unknown at design time (orientation-agnostic design) or for parts that must be re-oriented across multiple builds without re-validation.

IX.  REPRESENTATIVE APPLICATIONS

PA11 (Nylon 11, EOS PA 1101) is typically deployed in the following applications:

1)  Living hinges and snap-fit closures: Repeated-flexing applications such as dust-cap hinges, integrally moulded battery covers, and clip-on housings, exploiting the 45 % elongation at break.

2)  Automotive interior crash components: Glove-box latches, dashboard ducts, and other interior parts certified to non-splintering crash requirements (FMVSS 201 head-impact regions).

3)  Eyewear & wearables: Bio-based credentials and natural skin-tone-compatible dye chemistry make PA11 a leading choice for high-volume custom eyewear frames (Mykita, Hoet Cabrio).

4)  Sports protection equipment: Helmet liners, lattice-structured shin guards and elbow pads — energy absorption per unit mass is high due to the high elongation.

5)  Medical orthoses & prosthetic sockets: Patient-specific orthoses and prosthetic interfaces leveraging skin-contact biocompatibility certification and low water absorption.

X.  REFERENCES

[1]  EOS GmbH, “PA 1101 Polyamide 11 — Material data sheet,” EOS Polymer Solutions, 2024. [Online]. Available: https://www.eos.info/polymer-solutions/polymer-materials/data-sheets/mds-pa-1101

[2]  EOS GmbH, “PA 1101 ClimateNeutral — Material data sheet,” EOS, 2024. [Online]. Available: https://www.eos.info/en-us/polymer-solutions/polymer-materials/data-sheets/mds-pa-1101-climate-neutral

[3]  Arkema, “Rilsan PA11 Polyamide — Bio-based & High-Performance,” Technical Bulletin, 2023.

[4]  BASF Forward AM, “Ultrasint PA11 — Technical Data Sheet,” 2024. [Online]. Available: https://forward-am.com/material-portfolio/ultrasint-pa11/

[5]  ASTM D638-14, “Standard Test Method for Tensile Properties of Plastics,” ASTM International, West Conshohocken, PA, 2014.

[6]  ASTM D790-17, “Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics,” ASTM International, 2017.

[7]  ASTM D256-10, “Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics,” ASTM International, 2018.

[8]  ASTM D648-18, “Standard Test Method for Deflection Temperature of Plastics Under Flexural Load,” ASTM International, 2018.

[9]  ISO 527-2:2012, “Plastics — Determination of tensile properties — Part 2,” ISO, Geneva, 2012.

[10]  ASTM D2240-15, “Standard Test Method for Rubber Property — Durometer Hardness,” ASTM International, 2015.

[11]  G. Salmoria et al., “Mechanical properties of PA6/PA66 polymer mixed by selective laser sintering,” Polymer Testing, vol. 26, pp. 361–368, 2007.

(Image Resouce : Weerg)