Overview
EN ISO 4612:2018 - Plastics: Preparation of PVC pastes for test purposes - Planetary‑mixer method defines standardized procedures to prepare PVC pastes (plastisols) using a planetary mixer. It specifies two preparation procedures, Method A (single‑speed) and Method B (two‑speed), intended to produce reproducible pastes for laboratory testing, including rheological measurements used in resin designation and specification.
Key topics and technical requirements
- Scope and purpose: Preparation of PVC pastes from PVC resin, plasticizer and other ingredients for test purposes (rheology, process control, specification).
- Two methods:
- Method A (single‑speed) - suited to resins prone to heat build‑up. Mixing uses a single mixer speed and includes specific short interrupt/scrape steps and a total mixing time (document gives precise timing).
- Method B (two‑speed) - uses a higher secondary speed for shorter overall mixing time; often preferred for repetitive or production control work.
- Planetary mixer specification: Stainless‑steel bowl (700–1 200 g charge recommended), beater/bowl configuration where the beater both revolves and orbits (planetary action). Mixer power and speed relationships are defined (e.g., beater rotation around the bowl axis ≈ 60 min−1 ± 5; two‑speed secondary ~120 min−1 ± 10 where applicable).
- Conditioning: Resin must be free from agglomerates and conditioned at 23 °C ± 2 °C and (50 ± 5) % RH for 88 hours prior to use (reference to ISO 291).
- Mixing practice: Hand‑preblend resin and plasticizer to remove free plasticizer, follow timed mixing and scrape‑down steps, check paste temperature (temperature limits and corrective actions are described), and visually verify absence of lumps.
- Post‑mixing: De‑aeration under partial vacuum, transfer to covered beakers and storage at controlled atmosphere for testing.
- Documentation: Requirements for paste‑preparation reporting to ensure traceability of test samples.
Applications and who uses it
- Laboratories performing rheological testing of PVC resins and plastisols.
- Quality control and process‑control teams in PVC resin and plastisol manufacturing.
- R&D groups developing PVC formulations where consistent, reproducible paste preparation is critical.
- Test houses and certification bodies that require standardized sample preparation for comparative data.
Related standards
- ISO 291 (conditioning and testing atmospheres) is referenced for sample conditioning. Use EN ISO 4612:2018 together with applicable rheology or specification standards for PVC materials.
Keywords: EN ISO 4612:2018, PVC pastes, plastisols, planetary mixer, paste preparation, resin conditioning, Method A, Method B, rheological testing.
