ISO 1133-2:2011

Overview

ISO 1133-2:2011 specifies a laboratory method to determine the melt volume‑flow rate (MVR) and melt mass‑flow rate (MFR) of thermoplastics that are highly sensitive to time‑temperature history and/or moisture. It is a variant of the general MFR/MVR test (ISO 1133-1) with tighter control of temperature, timing and sample handling to reduce variability for moisture‑ or heat‑sensitive polymers. The standard applies where accurate, repeatable flow‑rate data are required for grades such as PET, PBT, PEN, polyamides and some thermoplastic elastomers - but may be unsuitable for materials whose rheology changes extremely during testing.

Key topics and technical requirements

• Scope and purpose: Test procedure tailored for materials whose rheological behaviour is influenced by hydrolysis, condensation or moisture uptake.
• Apparatus: Use an extrusion plastometer (cylinder, piston, die) meeting ISO 1133-1 requirements with additional controls.
• Temperature control:
  • Absolute deviation in the cylinder (0–70 mm above the die) must not exceed ±1 °C.
  • Relative temperature distribution over that region must not exceed ±0.3 °C with position and time.
  • Test temperature setting resolution: 0.1 °C or better.
• Die and measurement details:
  • Standard die dimensions as in ISO 1133-1 (e.g., length 8.000 ±0.025 mm, diameter 2.095 ±0.005 mm); a half‑size die may be used for very low‑viscosity materials.
  • MVR measured from piston displacement/time; MFR obtained by weighing extrudate or calculated from MVR using melt density at test conditions. A cutting device may be used if accuracy matches MVR.
• Sample conditioning & handling: Stringent pre‑treatment and drying instructions for moisture‑sensitive materials (see ISO 15512 for water content). Small variations in sample mass, form or handling can significantly affect results.
• Precision and reporting: Tighter procedural tolerances improve repeatability versus ISO 1133-1; test conditions should be specified in the material standard or agreed between parties.

Practical applications and users

Who uses ISO 1133-2:2011:

• Polymer manufacturers and compounders for quality control of moisture‑sensitive grades (e.g., PET, polyamides).
• Third‑party test laboratories validating MFR/MVR data for sensitive materials.
• R&D and materials development teams comparing rheological changes due to processing, moisture or degradation.
• Standards developers and procurement/specification engineers requiring reproducible flow‑rate metrics.

Why it matters:

• Provides more reliable MFR/MVR data for materials prone to hydrolysis, condensation or time‑temperature effects, improving material specification, processing set‑up and quality assurance.

Related standards

• ISO 1133-1 (standard MFR/MVR method)
• ISO 472 (plastics vocabulary)
• ISO 15512 (water content determination)
• ISO 307 / ISO 1628 (viscosity number for alternative characterization)

Keywords: ISO 1133-2:2011, MFR, MVR, melt mass‑flow rate, melt volume‑flow rate, thermoplastics, time‑temperature history, moisture sensitive, extrusion plastometer, plastics testing.