Overview
ISO 105-X11:1994 - Textiles - Tests for colour fastness - Part X11: Colour fastness to hot pressing - defines standardized laboratory methods to assess how textile dyes withstand hot-pressing conditions. The standard covers three press conditions: dry pressing, damp (humid) pressing and wet pressing. Specimens are pressed under controlled temperature, pressure and time and then evaluated for colour change and staining (crocking) using grey scales.
Key topics and technical requirements
- Test variants:
- Dry pressing: dry specimen pressed alone.
- Damp (humectant) pressing: dry specimen covered with a wet cotton adjacent fabric.
- Wet pressing: wet specimen covered with wet cotton adjacent fabric.
- Apparatus and layers: pair of smooth heated plates, heat-resistant sheet (3–6 mm thick), two layers of wool flannel (~260 g/m²) to form ~3 mm cushioning, and an uncoloured bleached cotton backing (100–130 g/m²).
- Pressure and time: plates apply a pressure of 4 kPa ± 1 kPa; typical pressing time 15 s.
- Temperatures: commonly used press temperatures are 110 °C ±2 °C, 150 °C ±2 °C and 200 °C ±2 °C; selection depends on fibre type and end-use (use the lowest-resistance fibre temperature in blends).
- Specimen preparation: standard specimen size 40 mm × 100 mm for fabrics and yarn-wound samples; fibre batts are formed into the same sized swatches and secured to cotton backing.
- Evaluation and conditioning: assess colour degradation and staining immediately after test and again after 4 h conditioning in standard textile test atmosphere (ISO 139: 20 °C ±2 °C, RH 65% ±2%). Use ISO 105-A02 (grey scale for change) and ISO 105-A03 (grey scale for staining) for scoring.
- Water and materials: use water of quality 3 for wet/damp tests. Reports must include standard reference, sample ID, procedure used, device temperature, and fastness grades (immediate and after conditioning).
Applications and users
- Textile manufacturers and dye houses: validate dye and finish resistance to iron/pressing processes used in garment manufacture and care.
- Quality assurance and test laboratories: routine quality control for production runs, supplier verification and compliance checks.
- Product development and R&D: evaluate new dyes, finishes and fibre blends for press durability.
- Care-labelling and performance specification: inform ironing instructions and consumer care guidance.
Related standards
Keywords: ISO 105‑X11, colour fastness to hot pressing, textile testing, dye fastness, hot pressing test, fabric care, textile quality control.