Overview
EN ISO 105‑X18:2007 - Textiles - Tests for colour fastness - Part X18: Assessment of the potential to phenolic yellowing of materials specifies a laboratory screening method to evaluate the susceptibility of textile materials to phenolic yellowing. The method is specific to yellowing caused by the reaction of phenolic compounds and oxides of nitrogen and does not address other causes of yellow discoloration. It is intended as a practical screening test to reduce phenolic-yellowing complaints by identifying at‑risk materials before shipment or use.
Key topics and technical requirements
- Scope & limitation: Designed only to detect potential for phenolic yellowing; a screening test that does not guarantee absolute absence of yellowing in service.
- Principle: Test specimens and a white control fabric are sandwiched between folded test papers, placed between glass plates, sealed in BHT‑free polyethylene film, compressed and incubated to accelerate phenolic reactions.
- Critical test conditions:
- Incubation at 50 ± 3 °C for 16 h ± 15 min.
- Applied mass on package: 5 ± 0.1 kg (test device weight).
- Use BHT‑free polyethylene film (~63 µm thick) to create an airtight package.
- Apparatus & materials:
- Glass plates (≈100 × 40 × 3 mm), test papers (cellulose, specified density and treatment), white polyamide control fabric known to yellow under the test, and the stainless‑steel test device.
- Assessment:
- Evaluate specimens and control fabric within 30 minutes of opening using the Grey scale for assessing staining (ISO 105‑A03) or instrumental assessment per ISO 105‑A04.
- Control fabric must yellow to at least Grade 3 on the grey scale to validate the test run.
- Test report: Must include reference to ISO 105‑X18:2007, sample identification and the numerical grey scale rating for staining.
Applications and who uses it
- Quality control laboratories in textile mills, dyehouses and finishing plants use the standard to screen fabrics, yarns and fibres for phenolic-yellowing risk.
- Product development teams and chemical formulators use the test to evaluate finishes, packaging materials and stabilizers.
- Importers, retailers and specifiers employ the method as part of acceptance testing to reduce customer complaints related to yellowing.
- Testing service providers and conformity assessment bodies include ISO 105‑X18 in test portfolios for colour‑fastness reporting.
Benefits: early detection of phenolic-yellowing propensity, informed corrective actions (material selection, packaging, additive changes), and reduced field failures and returns.
Related standards
- ISO 105‑A01 - General principles of testing (colour fastness series)
- ISO 105‑A03 - Grey scale for assessing staining
- ISO 105‑A04 - Instrumental assessment of staining
Keywords: phenolic yellowing test, colour fastness, ISO 105‑X18:2007, textiles, screening test, grey scale for staining, BHT‑free film, control fabric