Overview
ISO 8022:1990 defines a laboratory method to determine the wetting power of surface active agents (surfactants) by immersion. The test measures how quickly a raw cotton disc, held in a stainless-steel gripper, is wetted by a surfactant solution and begins to sink after trapped air is displaced. Results are expressed as wetting time versus concentration curves and compared with two standard surfactant curves to evaluate wetting performance.
Key topics and technical requirements
- Principle: Immerse a 30 mm raw cotton disc (conditioned per ISO 139) in a known concentration of surfactant solution; start a stopwatch at immersion and stop when the disc sinks of its own accord.
- Calibration: Determine wetting-time/concentration curves for two standard di-n-alkylsulfosuccinate solutions:
- Sodium di-n-heptylsulfosuccinate - first concentration 0.2 g/L
- Sodium di-n-hexylsulfosuccinate - first concentration 1.3 g/L
- Test series: Measure wetting time for each of five concentrations for both standards and for the surfactant under test (each concentration measured as the mean of 10 determinations).
- Apparatus & conditions:
- 1 000 ml low-form beaker (700 ml test solution)
- Stainless-steel cloth-immersion gripper designed to hold the disc ≈40 mm below the surface; gripper tips open ≈6 mm
- 30 mm punch for discs; stopwatch accurate to 0.1 s
- Test temperature nominally 20 °C ± 2 °C; water quality per ISO 2456
- Data handling: Plot wetting time against concentration (log-log paper recommended) and compare the test-agent curve with the two standard curves to estimate wetting power.
- Scope limits: Applicable to most surfactants used as wetting agents in neutral, slightly acidic or slightly basic baths; not applicable to highly basic mercerizing assistants or highly acidic carbonizing assistants.
- Reporting: Full identification of sample, cloth characteristics, method reference, water nature, temperature, plotted curves, and any deviations from the standard procedure.
Applications and users
ISO 8022:1990 is used by:
- Textile laboratories and quality control teams to evaluate wetting performance in washing, rinsing and softening processes
- Detergent and surfactant formulators assessing wetting agents for cleaning or fabric treatment
- R&D teams comparing surfactant efficacy and optimizing concentrations
- Regulatory or contract testing labs requiring a standardized wetting-power measurement
Practical uses include formulation selection for textile processing, performance comparison of surfactants, and routine QC of wetting agents.
Related standards
- ISO 139 - Conditioning of textiles (temperature and humidity)
- ISO 607 - Sample division for surfactants and detergents
- ISO 2456 - Water for tests (specification and test methods)
- ISO 3819 - Laboratory beakers
- ISO 3801, ISO 7211 - Textile fabric characterization (referenced for control cloth specifications)
Keywords: ISO 8022:1990, wetting power, surface active agents, wetting time, cotton disc immersion, surfactant testing, textile wetting, di-n-hexylsulfosuccinate, di-n-heptylsulfosuccinate.