Overview
EN ISO 9073-12:2004 - Textiles - Test methods for nonwovens - Part 12: Demand absorbency (ISO 9073-12:2002) - specifies a laboratory method to evaluate the absorbency of a fabric when one face is in contact with a liquid under mechanical pressure. Also called demand wettability, the method is intended for comparative testing of absorbent materials (especially nonwovens) and is not intended to simulate final in-use conditions of finished products.
Key Topics and Requirements
- Scope and purpose: Measures liquid uptake when one face contacts liquid under a controlled static pressure to compare absorbent materials.
- Apparatus essentials:
- Porous glass plate, Ø (60 ± 1) mm, porosity rating 2 (4 µm–90 µm) and calibrated flow rate (see Annex A).
- Siphon/reservoir assembly and U-tube; reservoir Ø ≈ 80 mm.
- Hydrophobic polyether–polyurethane foam pad (Ø 55 ± 1 mm, ~2 mm thick) and cylindrical weight such that foam+weight mass = (605 ± 5) g → imposed pressure ≈ (2.50 ± 0.05) kPa.
- Electronic balance (0.01 g resolution) and data acquisition system (≥ 4 readings/s; high-rate tests may require 8 Hz).
- Test specimens and conditioning:
- Cut five test pieces per sample, Ø (55 ± 1) mm.
- Condition samples per ISO 139; use test water per ISO 3696 at (20 ± 2) °C.
- Procedure summary:
- Attach test piece to foam pad, place on porous plate, record reservoir mass vs time until mass change over previous 5 s ≤ 1% of maximum absorbed mass.
- Clean porous medium between sets (e.g., sulfochromic acid) and use fresh test liquid for each set.
- Measured outcomes:
- Maximum absorbed mass (Af) - grams absorbed when equilibrium criterion met.
- Demand absorbency capacity (DAC) - Af divided by specimen mass (g/g).
- Maximum absorption rate (MAR) - largest absorbed mass change over a 1 s interval (g/s), calculated from fine time-sampled data.
Applications and Users
- Primary users: nonwoven manufacturers, independent testing laboratories, R&D teams, quality assurance and specification engineers.
- Typical applications:
- Comparative performance testing of wipes, hygiene materials, medical disposables, filtration and absorbent layers.
- Material selection and product development where relative absorbency under pressure is an important attribute.
- Note: Results support material comparison and specification; they do not replace real-use clinical or field testing.
Related Standards
- ISO 9073 series (Parts 1–11, 12, etc.) for other nonwoven test methods (mass/area, thickness, tensile, absorption, strike-through).
- ISO 139 (conditioning) and ISO 3696 (water for analytical use) - normative references within EN ISO 9073-12.
Keywords: EN ISO 9073-12:2004, demand absorbency, demand wettability, nonwovens test method, DAC, MAR, porous plate test, textile standard.
