Overview
ISO 17557:2003 - Plastics - Film and sheeting - Cast polypropylene (PP) films - specifies requirements and test methods for cast polypropylene films used mainly for packaging. The standard covers visual acceptability, dimensional tolerances, physical and barrier properties, packaging and marking, and the laboratory test procedures required to demonstrate compliance. It is intended for manufacturers, converters, quality laboratories and specifiers working with cast PP film, packaging film, and food-contact film applications.
Key topics and requirements
- Scope and classification: Films are classified into four types (homopolymer or copolymer; treated or untreated by corona/flame). This classification guides applicable property limits and marking.
- Appearance: Films must be free from visible flaws, wrinkles, stains or foreign matter that impair serviceability. Splices in rolls should be visibly marked.
- Dimensions and tolerances:
- Width tolerance: up to +5 mm above nominal width.
- Roll length tolerance: up to +1% above nominal length.
- Preferred core inside diameters: 76 mm or 152 mm.
- Thickness: average film thickness shall be within ±10% of the nominal value (examples given for 20–60 µm nominal thicknesses).
- Performance properties: The standard requires films to meet specified mechanical, optical and barrier properties (tensile strength and strain, haze for transparent films, water‑vapour transmission, wetting tension, dynamic coefficient of friction and threshold heat-sealing temperature). The threshold heat-sealing temperature is defined as the lowest temperature producing a seal strength of 3 N per 15 mm width.
- Testing and conditioning: Test procedures reference established ISO methods (e.g., ISO 291 for conditioning, ISO 527‑3 for tensile tests, ISO 4593 for thickness, ISO 14782 for haze, ISO 15106‑1/2/3 for water vapour transmission, ISO 8295/8296 for friction and wetting tension). Conditioning is typically at 23 ± 2 °C and 50 ± 5 % RH.
- Marking and packaging: Packages must indicate product name, classification (homopolymer/copolymer and treated/untreated), nominal thickness/width/length, manufacturing date and manufacturer/trademark.
Applications and users
- Film manufacturers and extruders producing cast polypropylene (PP) films
- Packaging engineers and converters specifying materials for food, consumer and industrial packaging
- Quality control and testing laboratories performing compliance testing and acceptance checks
- Product developers assessing barrier, optical and sealability properties for flexible packaging
Related standards
ISO 17557 references several normative test standards, including:
Keywords: ISO 17557:2003, cast polypropylene, PP films, packaging film, film thickness, tensile properties, water vapour transmission, corona treatment, wetting tension, heat-sealing temperature.
