Overview
ISO 16532-3:2010 defines a standardised turpentine test for assessing the grease resistance of mechanical greaseproof and glassine papers. The method provides an accelerated, comparative measure of how rapidly oils or greases (typical of foodstuffs) penetrate voids in uncoated papers where resistance is achieved by mechanical refining rather than coatings or internal sizing. It is not applicable to coated or internally treated grease-resistant papers (see ISO 16532‑1 and ISO 16532‑2).
Key topics and technical requirements
- Test principle: A 100 mm × 100 mm test piece is placed on white coated paper; a measured mound of sand saturated with coloured turpentine is applied. The elapsed time until a stain appears on the coated paper beneath the sand is recorded as the penetration time.
- Reagents:
- Pure gum spirits of turpentine (density 860–875 kg/m3 at 20 °C).
- Anhydrous calcium chloride and an oil‑soluble dye (e.g., Sudan red).
- Ottawa sand screened to pass 800 µm but retained on 630 µm.
- Test solution: 100 ml turpentine + 5 g CaCl2 + 1.0 g dye (aged, filtered and stored airtight).
- Apparatus and sampling:
- Tube (25 mm internal diameter), automatic pipette delivering 1.1 ml, watch glass, 5 g sand scoop, coated printing paper (recommended grammage 100–120 g/m2).
- Ten conditioned test pieces (10 × 100 mm × 100 mm), conditioned at 23 °C ± 1 °C per ISO 187.
- Procedure highlights:
- Add 5.0 g sand, then 1.1 ml test solution; start timer at last drop.
- Observe at specified intervals (every 15 s up to 1 min, every 1 min to 5 min, every 5 min to 30 min).
- If no stain within 1 800 s (30 min), record as >1800 s. Mean penetration time reported to two significant figures; report min/max and side-specific means if applicable.
- Precision: An international round‑robin demonstrated variable repeatability and reproducibility depending on sample greaseproof level; the standard includes guidance and Annex A results.
Applications
- Evaluating barrier properties of glassine and greaseproof papers used in food packaging, bakery and confectionery wrappers, and other grease‑sensitive packaging.
- Quality control, incoming material inspection, comparative R&D of mechanical greaseproof processes.
- Risk assessment for aesthetic grease spotting and permeation in paper packaging.
Who should use this standard
- Paper and board manufacturers (glassine/greaseproof grades)
- Independent testing laboratories and QC departments
- Packaging developers and converters for food products
- Regulatory and procurement teams specifying grease resistance requirements
Related standards
Keywords: ISO 16532-3:2010, grease resistance, turpentine test, glassine papers, greaseproof paper testing, paper and board standards, food packaging barrier testing.
Open preview (PDF)Paper and board — Determination of grease resistance — Part 3: Turpentine test for voids in glassine and greaseproof papers
