AATCC 8-2007 Colorfastness to Crocking: AATCC Crockmeter Method.
8. Conditioning
8.1 Prior to testing, precondition and condition the test specimens and the crock squares for crock testing as di- rected in ASTM D 1776, Conditioning Textiles for Testing. Condition each specimen for at least 4 h in an atmosphere of 21 ± 1°C (70 ± 2°F) and 65 ± 2% RH by laying each test specimen or crock square separately on a screen or perforated shelf of conditioning rack.
9. Procedures
9.1 Dry Crocking Test.
9.1.1 Place a test specimen on the base of the Crockmeter resting flat on the abrasive cloth with its long dimension in the direction of rubbing (see 13.6 and 13.7).
9.1.2 Place specimen holder over speci- men as an added means to prevent slippage.
9.1.3 Mount a white test cloth square, the weave parallel with the direction of rubbing, over the end of the finger which projects downward from the weighted sliding arm. Use the special spiral wire clip to hold the test square in place. Posi- tion the clip with loops upward. If the loops point downward they can drag against the test specimen.
9.1.4 Lower the covered finger onto the test specimen. Beginning with the finger positioned at the front end, crank the meter handle 10 complete turns at the rate of one turn per second to slide the covered finger back and forth 20 times. Set and run the motorized tester for 10 complete turns. Refer to individual specifications for any other required number of turns.
9.1.5 Remove the white test cloth square, condition (see 8.1) and evaluate as directed in Section 10. In the case of napped, brushed or sanded material when loose fiber might interfere with the rating, remove the extraneous fibrous material by pressing lightly on the crock circle with the sticky side of cellophane tape before evaluating.
9.2 Wet Crocking Test.
9.2.1 Establish technique (see 13.10) for preparing wet crock cloth squares by weighing a conditioned square, then thoroughly wet out white testing square in distilled water. Prepare only one square at a time.
9.2.2 Weigh dry crock square. Using a syringe tube, graduated pipette or auto- matic pipetter, draw up water in mL to 0.65 times weight of crocking square. If crocking square weight equals 0.24 gm, the mL used would be 0.24 × 0.65 = 0.16 mL. Lay crocking square on white plastic mesh over a dish. Apply water evenly over crocking square and weigh the wet square. Calculate wet pickup according to instructions in AATCC Methods 8 and 116, Colorfastness to Crocking test meth- ods. If needed, adjust the amount of water used to wet the square and using a new crocking square, repeat steps. When 65 ± 5% wet pickup is achieved, record the amount of water used. Draw up the re- corded amount of water into the syringe tube, graduated pipette or automatic pipetter for each wet crocking performed during the current day. Repeat this process each day.
9.2.3 Avoid evaporative reduction of the moisture content below the specified level before the actual crock test is run.
9.2.4 Continue as directed in 9.1.
9.2.5 Air dry the white test square, then condition (see 8.1) before evaluating. In the case of napped, brushed or sanded material when loose fiber might interfere with the rating, remove the extraneous fibrous material by pressing lightly on the crock circle with the sticky side of cello- phane tape before evaluating.AATCC 8 pdf download.