ASTM D69:2006 pdf free download – Standard Test Methods for Friction Tapes.
36. Significance and Use
36.1 The tendency of a friction tape to discolor copper is an indication of the level of sulfur or sulfur containing curatives present in the adhesive compound.
37. Apparatus
37.1 copper Rod—Clean, bright, and smooth. Approximately ‘/4 in. (6.4 mm) in diameter and 3 in. (75 mm) in length.
37.2 Test Tube, capable of being sealed.
37.3 Oven, maintained at 212 ± 9 °F (100 ± 5 °C).
38. Procedure
38.1 Wind five superimposed layers of tape on the copper rod raking care to avoid touching the surface of the rod near the tape layers.
38.2 Place the sample in a closed test tube and heat at 212 °F(100 °C) for 16 h.
38.3 Cool the sample and visually inspect for the presence of a blue-black discoloration on the surface of the rod at the edge of the tape.
39. Report
39. 1 For each sample roll, report the presence or absence of discoloration.
40. Precision and Bias
40.1 No statement is made about either the precision or the bias of this test method since the result merely states the presence or absence of discoloration.
PARALI4EI2ISM
41. Significance and Use
41 .1 Parallelism is an indicator of the potential of a roll of friction tape to resist fraying at the edge when the roll is unwound. Parallelism is also an indicator of the overall quality and the degree of care which has been taken in slitting the tape.
42. Test Specimen
42.1 Make the test specinien from a single layer of tape 16 in. (400 mm) in length unwound from the sample roll.
43. Procedure
43.1 Tear the test specimen approximately in half lengthwise, assisting the tearing by first slitting one end for about Y2 in. (12 mm) with a knife or a razor blade.
43.2 Cleanly cut a 2 in. (50 mm) length from each end of one of the torn halves.
43.3 Fold the remaining 12 in. (300 mm) length in half to bring the two ends together while mating along one edge.
43.4 Using a steel rule graduated to read ½2 in. or 1.0 mm, measure the difference in width between the two mated ends and record that distance to the nearest ½2 in. as the deviation from parallel.
44. Report
44.1 For each sample roll, report the measured deviation from parallel.
49.3 Roll the roller over the specimens once at a slow uniform rate so that the 8 in. (200 mm) length is passed over in approximately 8 s, taking care that the only downward pressure on the specimens is due to the weight of the roller.
49.4 Pick up the two specimens from the end last in contact with the roller, using one pair of tweezers for each specimen.
49.5 Pull the ends of the specimens apart horizontally, keeping the forearms in contact with a rigid support. such as the edge of the table. The rate at which the specimens are separated shall be steady and not exceed I in./s. Observe the point of separation of the two specimens, disregarding the last 1 in. (25 mm).