AATCC 81-2016 pH of the Water-Extract from Wet Processed Textiles.
3. Terminology
3.1 bleaching, n.—elimination of un- wanted coloring matter from a textile sub- strate by oxidative or reductive chemical treatment.
3.2 pH, n.—the negative logarithm of the effective hydrogen ion concentration or hydrogen ion activity in gram equiva- lents per liter used in expressing both acidity and alkalinity on a scale whose values run from 0-14 with 7 representing neutrality, numbers less than 7 increasing acidity and numbers greater than 7 in- creasing alkalinity.
3.3 wet processing, n.—in textile manufacturing, a collective term for processes included in preparation, dyeing, printing and finishing in which the textile material is treated with a liquid, normally water, or with chemicals in solution or dispersion in a liquid.
4. Safety Precautions NOTE: These safety precautions are for information purposes only. The precautions are ancillary to the testing procedures and are not intended to be all inclusive. It is the user’s responsibility to use safe and proper techniques in handling materials in this test method. Manufacturers MUST be consulted for specific details such as material safety data sheets and other manufacturer’s recommendations. All OSHA standards and rules must also be consulted and followed.
4.1 Good laboratory practices should be followed. Wear safety glasses in all laboratory areas.
4.2 All chemicals should be handled with care.
5. Uses and Limitations
5.1 pH can be used to determine the suitability of wet processed textiles for subsequent dyeing and/or finishing operations or to evaluate the washing and/or neutralizing efficiency following any wet processing operation.
5.2 This method should be used in conjunction with AATCC Test Method (TM) 144, Alkali in Wet Processed Textiles: Total, in order to quantitatively determine the amount of an alkali present. While pH gives an indication of relative alkali or acid content, the exact amount can be masked by the presence of strong buffering agents.
6. Apparatus and Materials
6.1 pH meter with 0.1 unit graduations.
6.2 Beakers, glass, 400 mL.
6.3 Buffer solutions, pH 4.0, 7.0, 10.0 or others as needed.
7. Calibration
7.1 Calibrate the pH meter in accor- dance with the manufacturer’s instruc- tions. Select buffer solutions for calibra- tion which are in the estimated range of the specimens’ pHs.
8. Specimens
8.1 Use a 10 ± 0.1 g specimen of the material to be tested. If the specimen is difficult to wet out, then it should be cut into small pieces.
9. Procedure
9.1 Boil 250 mL of distilled water at a moderate rate for 10 min. Immerse the specimen, cover the beaker with a watch glass and boil for an additional 10 min.
9.2 Allow the covered beaker and con- tents to cool to room temperature. Remove the specimen with tweezers, allowing the excess liquid to drip back into the extract.
9.3 Determine the pH of the extract using a pH meter operated according to manufacturer’s instructions.AATCC 81 pdf download.