Overview
ISO 1110:2019 specifies a standardized method for the accelerated conditioning of test specimens made from polyamides (PA) and copolyamides. The procedure is intended to bring specimens quickly to an equilibrium moisture content close to that obtained in the standard atmosphere 23 °C / 50 % RH, enabling reproducible mechanical and physical testing. The method applies to filled and additive-containing grades but excludes grades with more than 2 % mass fraction of extractables.
Key topics and technical requirements
- Conditioning environment: specimens are stored at 70 °C ± 1 °C and a psychrometric temperature difference of 10 °C ± 0.3 °C (corresponding to 62 % ± 1 % RH) until they reach at least 95 % of equilibrium moisture.
- Apparatus options:
- Preferred: a cabinet with closed air circulation (fan) capable of holding the specified temperature and humidity tolerances.
- Where a cabinet is not available: oven (70 °C ± 1 °C) plus a closed container (e.g., desiccator) partly filled with a saturated aqueous potassium iodine solution per ISO 483. Note: specimens may become slightly discoloured by iodine.
- Monitoring and acceptance:
- Use an analytical balance accurate to 0.1 mg.
- After each conditioning interval, specimens are removed, cooled for 1 hour at 23 °C / 50 % RH, and weighed.
- Conditioning is complete when three consecutive weighings fall within 0.1 % tolerance.
- Specimens must be placed in 23 °C / 50 % RH for at least 1 hour before final testing.
- Timing: Table 1 in ISO 1110 gives recommended conditioning periods depending on polyamide type and specimen thickness; minimum intervals between weighings are not less than 1 day.
- Reference procedure: in cases of dispute the cabinet method (closed-circulation cabinet) is the authoritative reference.
Applications and who uses it
- Material testing laboratories performing mechanical, thermal or dimensional tests on polyamides.
- Quality control and production labs in plastics manufacturing, injection molding and compounding to speed up sample preparation.
- R&D teams evaluating moisture-sensitive properties of PA grades and filled compounds.
- Certification bodies and standards committees comparing accelerated vs. standard conditioning results.
Practical benefits include dramatically reduced conditioning times (e.g., a 4 mm PA66 specimen can take more than a year to equilibrate at 23 °C/50 % RH without acceleration) while maintaining moisture levels close to the standard atmosphere.
Related standards
- ISO 291 - Plastics: standard atmospheres for conditioning and testing (23 °C / 50 % RH reference).
- ISO 483 - Plastics: small enclosures using aqueous solutions to maintain constant humidity (used for potassium iodine solution guidance).
Keywords: ISO 1110:2019, polyamides, accelerated conditioning, moisture conditioning, 70 °C conditioning, 23 °C/50 %RH, ISO 291, ISO 483.