Overview
ISO 13229:2010 specifies a laboratory method for isolating the PVC resin from unplasticized poly(vinyl chloride) (PVC‑U) pipes, fittings or compounds used in thermoplastics piping systems for non‑pressure applications. The standard details the separation (isolation) procedure required so that the resin’s viscosity number (reduced viscosity) and K‑value can be determined (the viscosity determination itself is performed according to ISO 1628‑2).
Key topics and requirements
- Scope: Applies to PVC‑U resin recovered from pipes, fittings or compounds; only the resin separation method is specified in ISO 13229:2010.
- Limitations: Presence of other additives or other polymers (e.g., PMMA) that are soluble in THF but insoluble in methanol can invalidate the method.
- Reagents: Stabilized tetrahydrofuran (THF) and methanol are used for dissolution and precipitation respectively. Proper solvent handling and recovery are required for safety and regulatory compliance.
- Apparatus: Basic laboratory equipment including glass vessels, magnetic stirrer, centrifuge (50 ml tubes), filtering funnel and filter paper, desiccator, and (if needed) bath heater and Pasteur pipette.
- Procedure (summary):
- Cut ~2 g (2.5 g for high loadings) sample from pipe/fitting/compound.
- Dissolve in ~50 ml THF with stirring (heat gently if needed) until fully dissolved.
- Centrifuge the solution (~40 min) and decant the clear THF solution.
- Precipitate polymer by careful addition of methanol (up to 10:1 methanol:THF), filter and wash the precipitate with methanol.
- Dry precipitated resin (minimum 12 h at 50 °C in vacuum desiccator).
- Determine viscosity number per ISO 1628‑2 (use 0.250 g resin per solution in cyclohexanone).
- K‑value: Calculate according to the Fikentscher relationship included in the standard; Annex A provides a table linking viscosity number and K‑value. Reported accuracy for K is ±2.
- Reporting: Test report must reference ISO 13229:2010, identify the test item, list viscosity number and K‑value, note deviations or incidents, and give test date.
Applications and users
ISO 13229:2010 is used by:
- Manufacturers of PVC‑U pipes and fittings for quality control and product specification.
- Independent testing laboratories performing material characterization of PVC‑U.
- R&D teams developing or reformulating PVC compounds for non‑pressure drainage and sanitation systems.
- Certification bodies and regulators assessing compliance of thermoplastics piping systems.
Keywords: ISO 13229:2010, PVC‑U, viscosity number, K‑value, resin separation, THF, methanol, thermoplastics piping systems, ISO 1628‑2.
Related standards
- ISO 1628‑2 - Determination of polymer viscosity in solution (viscosity number method) - used for the actual viscosity measurement and calculation of K‑value.
