Overview
ISO 18066:2015 specifies an automatic test method for determining the boiling water shrinkage of manmade multifilament yarns (polyester, polyamide, polypropylene, cellulose‑based, etc.). It applies to non‑textured and textured multifilament yarns with linear density < 3 000 dtex and is not applicable to partially oriented yarns. The standard gives requirements for sampling, specimen preparation, test apparatus, test conditions and calculation of shrinkage (%) after thermal treatment in boiling water.
Key topics and technical requirements
- Scope and applicability: Multifilament filament yarns; only the automatic method is specified.
- Sampling and specimen preparation: Minimum lab sample sizes (minimum 20 tests per lot; at least 2 specimens per package) and instructions for winding skeins with specified set linear density (e.g., set T = 2 500 dtex for nominal ≤ 400 dtex; ~10 000 dtex for > 400 dtex to ~3 000 dtex).
- Apparatus:
- Automatic shrinkage tester with specimen holder (>600 mm), length‑measuring resolution of 0.05 mm and auto tension application. A small 2.5 cN hanging weight is used to avoid entanglement.
- Boiling water container adjustable to 100 °C (±3 °C) big enough to immerse the specimen holder.
- Ventilated oven for controlled drying (interior ≥ 600 mm; temperature control ±3 °C).
- Tension control: Tension is calculated per the standard using the specified tension per unit linear density: 0.05 ± 0.005 cN/dtex for non‑textured yarns and 0.20 ± 0.02 cN/dtex for textured yarns.
- Test cycle and conditioning: Precondition per ISO 139. Equilibrium times: >2 h before treatment, >4 h after. Immerse specimens in boiling water (with 1 g/L wetting agent if used) for 30 ± 5 min. Drain for 10 min and dry in oven at 55 ± 3 °C for 30 min (or air‑dry to equilibrium).
- Measurement and calculation: Measure straightened length before and after treatment (measurements to 0.1 mm accuracy). Boiling water shrinkage (BWS) is expressed as a percentage:
BWS = (L0 − L1) / L0 × 100
where L0 = length before treatment, L1 = length after treatment.
- Precision: Annex A reports repeatability and reproducibility data across materials (repeatability r ≈ 0.08–0.24; reproducibility R up to ≈ 1.51 for some yarn types).
Applications and who uses it
ISO 18066 is used for quality control, product specification, R&D and supplier acceptance testing in the textile industry. Typical users:
- Yarn manufacturers and spinners (multifilament yarn quality)
- Textile testing laboratories and third‑party test houses
- Textile mills and fabric converters assessing dimensional stability
- Procurement and compliance teams specifying shrinkage limits in contracts
The standard helps ensure consistent measurement of boiling water shrinkage for manufacturing control, performance claims and comparative testing.
Related standards
- ISO 139 (standard atmospheres for conditioning and testing)
- ISO 3696 (water for laboratory use)
- EN 14621 and BISFA test methods (related filament yarn test methods)
- ISO 8160 / ISO 10132 (textured filament yarn terminology and definitions)
Keywords: ISO 18066, boiling water shrinkage, manmade filament yarns, multifilament yarn test, textile testing, automatic shrinkage tester, dtex, yarn shrinkage test.