The Exchange Test Method
LABORATORY TEST METHOD NO. H-4: TOTAL ABSORBENCY AND ABSORPTIVE CAPACITY PERSONAL HYGIENE PRODUCTS
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PURPOSE:
To determine total absorbency and absorptive capacity of personal hygiene products. Absorbency reflects the ability of a specimen to absorb and hold moisture, while absorptive capacity reflects the ability of a specimen to absorb and hold moisture in relation to its own dry weight. Greater absorbency and absorptive capacity are desirable for comfort and hygienic reasons.
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PRINCIPLE:
Test specimen is weighed then immersed in saline solution under controlled conditions and weighed again.
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APPARATUS AND MATERIALS:
- 3.1 Mettler PE 24 scale, or its equivalent.
- 3.2 Bull clips or similar clips, as many as needed.
- 3.3 1% saline solution at 38°C (100°F).
- 3.4 Digital countdown timer.
- 3.5 Preferably stainless steel sink. 4.6 20 by 43 mm (8 by 17 in. ) wire screen rack with 6 to 12 mm (1/4 to 1/2 in. ) openings.
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PROCEDURE:
- 4.1 Weigh 10 specimens individually and record the weight of each specimen.
- 4.2 Fill the sink with 1% saline solution at 38°C (100°F) so that the specimen can be submerged completely in the solution.
- 4.3 Maintain the temperature of the saline solution at 38°C (100°F) .
- 4.4 Mount the specimen tightly on wire rack (liner facing up), and fasten each corner with a clip.
- 4.5 Place the assembly (rack with specimen mounted) on the scale platform. Adjust the scale to read zero.
- 4.6 Submerge the specimen assembly in the saline solution for 5 minutes.
- 4.7 Remove the specimen assembly and drain at 45° angle for 3 minutes.
- 4.8 Weigh the specimen assembly again. Record the weight. This weight represents total absorbency.
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5. EVALUATION:
Net absorbency divided by weight of dry personal hygiene product = absorptive capacity.
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6. REPORT
- 6.1 Total absorbency is the same as that in step 4.8.
- 6.2 The absorptive capacity is calculated as follows: Absorptive Capacity = Total Absorbency / Dry weight of the specimen