There are two methods for the PH value test of ultra thin sanitary napkin, namely beaker dipping method and surface dipping method. If it is arbitration inspection, it must be carried out according to surface impregnation.
Take a piece of sample, cut off the sticker, weigh 1g (accurate to 0.001g) of the sample from the middle, put it into a 100mL beaker, add mL deionized water (or distilled water), and vigorously stir the glass rod for 10min with a stirring rod. The composite electrode of the pH meter is placed in the beaker to read the data.
Take a sample, put the self-adhesive side down on the test bench, put mL of deionized water (or distilled water) close to the surface of the sample, slowly pour the sample into the sample within 1min, and the time will start to count down after the water. After 3rain, the composite electrode was attached to the water receiving surface of the sample, and the data was read 1 min after attachment.
The pH value test of ultra thin sanitary napkin should pay attention to: (1) The pH value meter must be equipped with a composite electrode, which must be calibrated with a standard buffer solution before the test; (2) After each test, rinse the electrode with distilled water and remove the residue with filter paper. (3) When using the second method, if there is too much polymer water-absorbent resin in the sample, an appropriate amount of water should be added within 1 min until a small amount of free water appears. on the surface of the specimen and start timing immediately.