AATCC 27-2004 Wetting Agents: Evaluation of Rewetting Agents

AATCC 27-2004 Wetting Agents: Evaluation of Rewetting Agents. 6. Procedure 6.1 Application of rewetting agenta solution of the rewetting agent is prepared by pouring 100 mL of hot water over the required amount of the product in a small beaker or casserole. This solution is heated above 97°C (200°F) for a moment and then is diluted with hot water to a final volume of1 L. The temperature of the solution in the padder box for application should be 70土3°C(158土5°F) 6.2 The padder is adjusted to a uniformly firm squeeze from side to side. On a household wringer it has been found that a dozen half turms of the wing nuts from the place where they just begin to take hold is satisfactory. 6.3 A strip of the selected cotton gods is padded three timtes through the solution of the rewetting agent. Three times through ensures thorough and uniform penetration of the cloth. The pickup should be from 60-90%. 6.4 The padded cloth is dried in air at approximately 82*C (180*F) for 30 min. 6.5 Four strips of padded cotton are prepared for each rewetting agent representing, respectively, four concentrations for each product to be tested. Concentrations generally suitable are 2.50, 5.0, 10.0 and 20.0 g of rewetting agent per liter. 6.6 Rewetting- a square of the padded, dried and conditioned cloth is mounted in the embroidery hoop. The burette containing either distilled water or tap water, whichever is desired for the test, is adjusted so that it delivers one drop of waterat21土19C(70土2*F) approximately every 5 s. The surface of the taut cloth is held about 1 cm (0375 in) below the tip of the burette and the stop- watch is started just as the drop flls on the cloth. The watch is stopped when the liquid on the surface of the cloth loses its specular reflective power. This point is determined by placing the hoop between the observer and a source of lightsuch as a window- at such an angle that the specular reflction of light from the surface of the flttened drop can plainly be seen. As the drop is gradually absorbed the area of this tiny miror diminishes and finally vanishes entirely leaving only a dull wet spot behind. It is at this moment that the watch is stopped. 7. Evaluation 7.1 Readings of rewetting time are made so easily and quickly that ten are taken for each...