Overview - EN ISO 4608:2023 (Plastics - Determination of plasticizer absorption at room temperature)
EN ISO 4608:2023 specifies a laboratory method to determine the quantity of plasticizer absorbed by homopolymer and copolymer resins of vinyl chloride (PVC) at room temperature. Applicable to PVC general‑purpose resins and filler resins designated "G" and "F" in ISO 24024‑1, this test gives a practical indication of a resin’s suitability for producing plasticized dry blends.
Key topics and technical requirements
- Scope and principle: An excess of plasticizer is added to a measured mass of resin; after a defined contact time the mixture is centrifuged and the amount of plasticizer retained by the resin is determined.
- Apparatus and materials: specifies ordinary laboratory equipment plus precision balance (±0.1 mg), burette or dispenser (≈50 cm3), a horizontal‑rotor centrifuge (acceleration under test conditions 24 500 to 29 500 m·s‑2), and specific centrifuge tubes (conical bottom with 0.8 mm hole or tubes with sieve plate).
- Sample sizes and conditions: typical test uses 2.000 g ±0.200 g resin and ~4 cm3 plasticizer (smaller tube option: 1 g resin and 2 cm3 plasticizer). Centrifuge temperature must be controlled so mixture temperature ≤30 °C after 60 min.
- Absorbent blank and alternatives: cotton wool (pharmaceutical quality, ≈100 mg) or filter paper is used to trap excess plasticizer; alternatives (glass wool, PTFE‑coated polyester felt) are permitted if equivalent.
- Plasticizers covered: Bis‑(2‑ethylhexyl) phthalate (DOP, CAS 117‑81‑7) and Bis‑(3,5,5‑trimethylhexyl) phthalate (DINP, CAS 28553‑12‑0 or 68515‑48‑0) with specified density, refractive index and viscosity ranges. Note: DOP is no longer used in Europe due to hazardous classification.
- Procedure and reporting: clauses detail blank measurement, weighing, addition of plasticizer, centrifuging, calculation and expression of results, and required test report elements.
Practical applications and users
- Product development and quality control: resin producers and compounders use EN ISO 4608:2023 to assess plasticizer uptake for formulation of dry blends and to predict processing behaviour.
- Purchasing and specification: purchasers of PVC resins can specify this test to verify compatibility with intended plasticizers and blend recipes.
- Regulatory and compliance testing: laboratories performing material characterization or conformity testing for PVC products.
- R&D teams evaluating new plasticizers (e.g., DINP) or filler effects on absorption at room temperature.
Related standards
EN ISO 4608:2023 is the up‑to‑date method to quantify room‑temperature plasticizer absorption for vinyl chloride resins, supporting reliable formulation and quality assessment of plasticized PVC products.
