ISO 105-C06: Assessing textile colorfastness to laundering

The ISO 105-C06 standard specifies methods for determining the resistance of the color of textiles of all kinds and forms to domestic or commercial laundering procedures, typically those used for normal household articles. This test is crucial for assessing how a textile's color will perform under repeated washing, which involves the combined effects of:

• Detergent and water: Exposure to the chemical solution.
• Temperature and time: The specific conditions of the wash cycle.
• Alkalinity/bleaching: The chemical environment created by the wash solution (which may include a bleach component like sodium perborate in some variants).
• Abrasive action: Mechanical agitation provided by the launder-ometer (wash wheel) and stainless steel balls.

Principles of the test

1. Composite specimen: A specimen of the textile being tested is sewn into contact with a specified adjacent fabric, often a multifiber fabric (which contains strips of different fiber types like cotton, wool, silk, etc.) or two single-fiber adjacent fabrics.
2. Laundering: This composite specimen is placed in a stainless steel pot with a prepared reference detergent solution (e.g., ECE 'B' phosphate-based detergent) and a specified number of steel balls. The pots are then mechanically agitated in a launder-ometer at a specific temperature and for a set time (e.g., 30 minutes).
3. Rinsing and drying: After the wash cycle, the specimen is rinsed and then dried, typically in air at a temperature not exceeding 60°C.
4. Assessment: The final results are assessed using:

• Grey scale for assessing change in color (ISO 105-A02): To determine the degree of color loss or change in the tested specimen.
• Grey scale for assessing staining (ISO 105-A03): To determine the degree of staining on the adjacent fabric(s).

The various sub-parts of the ISO 105-C06 test (like A2S, B2S, C2S, etc.) specify different conditions, such as temperature (e.g., 40∘C, 50∘C, 60∘C), the number of steel balls, and the presence of a bleaching agent (like sodium perborate tetrahydrate), to simulate different severity levels of washing. The ‘S’ designation (e.g., C2S) indicates a single test which approximates one typical commercial or domestic laundering.