ISO 1133-2:2011 is an ISO test method used to determine melt mass-flow rate (MFR) and melt volume-flow rate (MVR) for thermoplastics that are sensitive to time-temperature history and/or moisture.
It is typically selected when standard melt flow testing conditions do not adequately control material residence time or temperature tolerances, and tighter control is needed to reduce result variability. If you are not sure whether Part 2 is appropriate for your polymer grade and lab setup, talk with our team.
ISO 1133-2:2011 — Plastics — Determination of the melt mass-flow rate (MFR) and melt volume-flow rate (MVR) of thermoplastics — Part 2: Method for materials sensitive to time-temperature history and/or moisture
ISO 1133-2 is part of the ISO 1133 melt flow standards family. It addresses situations where the polymer’s flow behavior can change measurably during the test due to thermal exposure history and/or moisture effects.
This standard is commonly used for incoming material verification, lot-to-lot comparison, process stability checks, and data reporting where tighter control of test exposure conditions is required.
Quick Definition
What it is: A melt flow test method for determining MVR and/or MFR using tighter controls intended for moisture-sensitive and/or thermally sensitive thermoplastics.
What it measures: Melt volume-flow rate (MVR) and melt mass-flow rate (MFR) under specified temperature and load conditions, using a controlled extrusion plastometer workflow.
Why it is different: Compared with ISO 1133-1, it tightens tolerances on cylinder temperature and the time the material is subjected to that temperature, and it includes guidance related to preparation/handling of moisture-sensitive materials.
What This Standard Covers
ISO 1133-2 specifies a procedure for determining MVR and MFR for thermoplastic materials that show high rheological sensitivity to the time-temperature history experienced by the sample during testing and/or to moisture.
It is intended to improve repeatability and reproducibility for these sensitive materials by controlling the time-temperature exposure more tightly than a general melt flow method.
Why This Standard Matters in Testing
For some thermoplastics, small differences in thermal exposure (and/or moisture state) can shift flow results enough to mask real lot differences or create false rejects. ISO 1133-2 is used when a lab needs better control over the sample’s time at temperature and better handling discipline for moisture-sensitive materials.
In practical QA/QC workflows, this standard can be important when melt flow is used as a release metric, a supplier qualification check, or a process-change comparator where lower result scatter is a priority.
Common Materials, Product Types, or Applications Covered
ISO 1133-2 is applied to thermoplastics where melt flow behavior is notably affected by thermal history during the test and/or by moisture. Typical examples include polymers and compounds where residence-time sensitivity, degradation risk, or moisture effects are a known concern.
Common use cases: Resin receiving inspection, compound qualification, production monitoring, and reporting melt flow values for materials where a tighter-control method is specified by a customer, internal procedure, or material document.
Common Test or Verification Workflow
Most labs run ISO 1133-2 as a controlled melt flow procedure on an extrusion plastometer at an agreed (or specified) temperature and load condition for the material.
Common workflow: Condition or prepare the sample as required for moisture-sensitive materials, heat and load the plastometer per the specified condition, tightly control the time at temperature, and determine MVR and/or MFR from the extrusion output and measurement approach used by the instrument.
Practical caution: For sensitive materials, small differences in preheating time, handling between drying and test, and temperature stability can have an outsized impact on reported flow values.
Equipment Commonly Used for This Standard
ISO 1133-2 is typically performed using a melt flow indexer / extrusion plastometer configured to control cylinder temperature and timing tightly, and to measure flow output in a repeatable, operator-independent way when required.
Common equipment: Extrusion plastometer (melt flow tester) with stable temperature control, timed test sequencing, appropriate loads, and a measurement approach for MVR and/or MFR (including options that support mass measurement or calculation from volume using melt density when applicable).
If you are selecting a melt flow tester configuration for sensitive materials and need help aligning automation level, timing control, and reporting needs, you can request a detailed quote for an ISO 1133-2-focused setup.
How to Read This Designation or Revision
ISO 1133-2 identifies Part 2 of the ISO 1133 series for melt mass-flow rate (MFR) and melt volume-flow rate (MVR) testing of thermoplastics.
:2011 indicates the published year/edition associated with this part. When documenting compliance, labs typically record the cited edition along with the material, the test condition (temperature and load), and whether MVR, MFR, or both are reported.
Related Standards, Methods, or Frameworks
ISO 1133-1: The standard (general) method in the ISO 1133 family; ISO 1133-2 is used when tighter control of time-temperature exposure and moisture-sensitive handling considerations are needed.
ASTM D1238: A widely used melt flow rate standard often referenced in similar purchasing and reporting workflows; it may be cited by customers depending on region or specification.
Get help choosing an ISO 1133-2 test setup
For ISO 1133-2 work, instrument control of temperature stability and timing can matter as much as the base melt flow capability. If you share your polymer type, target conditions, and reporting requirements, we can help scope a practical system and accessories package—contact our team.