AATCC 43-2004 Wetting Agents for Mercerization

AATCC 43-2004 Wetting Agents for Mercerization. 5. Apparatus and Materials 5.1 Beakers, 250 mL. 5.2 Mohr measuring pipettes (0.1 grad- uation), 1 or 2 mL. 5.3 Volumetric transfer pipettes, 100 mL. 5.4 Stopwatch. 5.5 Scissors. 5.6 Ruler. 5.7 Cotton yarn, greige (unboiled), 40/2 combed peeler, preferably in form of chain warp or skein (see 9.1). 5.8 Standard mercerizing penetrant against which comparisons can be made. 5.9 Mercerizing caustic soda with a specific gravity of 48-52% Tw (271-299 g NaOH per liter of soln). Allow to stand several hours (until clear) after preparation. 5.10 Log-log coordinate paper No. 46- 7083 from Keuffel & Esser Co., or No. 340-L21 from Eugene Dietzgen Co. 6. Procedure 6.1 Into each of three 250 mL beakers measure out 100 mL of the mercerizing caustic soda solution at 26 ± 3°C (78 ± 5°F). Pipette into one beaker 0.75 mL, into the next 1.00 mL and into the third beaker 1.25 mL of the mercerizing penetrant using a suitable small pipette. Mer- cerizing wetting agents all seem to be liquids. Stir the contents of each beaker until the penetrant is completely dissolved in the caustic soda. These solutions are allowed to stand until all air bubbles have risen to the surface. It should be particularly noticed if the penetrant remains well dispersed or dissolved because the separation of an immiscible layer on the surface would entirely vitiate the results and give false values. 6.2 From the greige (unboiled), 40/2, combed peeler cotton yarn, cut a bundle of 120 parallel ends, 25 mm (1 in.) in length. This bundle of yarn ends is dropped carefully onto the surface of one of the caustic solutions of penetrant, and the time required for complete wetting of all the ends is noted with a stopwatch. The average of five determinations is taken as the sinking time for that concentration. 6.3 In like manner the average sinking time is determined at the other two concentrations for the penetrant under test. Then the average sinking times for the standard at the same three concentrations are determined by the same procedure. 7. Evaluation 7.1 The three average sinking times to the nearest tenth second for the product under test and for the standard are plotted as ordinates on loglog coordinate paper against concentrations of wetting agent in milliliters per 100 mL of caustic soda solution. Straight lines should be obtained when the points...