Tape abrasion test

The previously mentioned tests that can be used to determine if a plastic is abrasive to other surfaces are not particularly suited to evaluation of the abrasivity of plastics that are normally manufactured as flexible webs. Web materials with thicknesses less than about one millimeter pose the problem that they usually need to be adhered to some other surface to allow testing them as bushings, thrust washers, or blocks for block-on-ring tests. This can be done and is done, but two other tests Imve been developed that are particularly useftil for web materials the ball-on-plane test and the tape abrasion test (14). The ball-on-plane test, lich is shown schematically in Figure 8, reciprocates a spherical rider on a web test sample while the sample rotates slowly at less than 1 revolution per minute. The rider would see mostly fresh surface if allowed to run only one revolution, but in practice this test is usually run for longer test durations (from 10 minutes to 40 hours). When the test is run for more than an hour, the web counterface is changed every hour the rider is simply lifted off the test surface. Volume loss on the ball rider is the test metric. Wear volume is measured from the ball scar diameter and this measurement can be made in situ on the test apparatus. 

The tape abrasion test wilt sometimes be more effective than the ball-on-plane test in measuring abrasivity depending on the tribosystem that is being simulated. It is also more suited to testing rider materials that are not easily made into spheres or hemisphericat-ended pins. The rider is a small flat of material. 

In summary, the ball-on-plane and the tape abrasion test are valuable tools for measuring the abrasivity of plastic or other flexible webs to mating surfiices. It better simulates web conveyance systems than the abrasivity tests that use abrasives that are not typical in tritosystems of interest. 

Figure 9. Schematic of the tape abrasion test. The tape can be a boncted abrasive or any web material of interest (Reproduced with permission of Bud Labs).

The abrasion tests were performed with a Stoll flex abrader. The yarn was wound on a card, taped In a group, and cut to the dimensions indicated In Figure 7. The yarn treated with conventional starch exhibited significantly greater abrasion resistance qualities than the yarn treated with degraded starches. 

Armstrong Abrasion Test (ASTM D1242) This test measures abrasion resistance of flat surfaces by drawing abrasive tape, under load, over test specimens at a slip rate of 15.75 g/cm. With No. 320 abrasive under a 6.8 kg load, weight loss was measured after 200 revolutions (1 hr, 40 min.). 

Scotch-tape test [13,16-20] Abrasion test [18,21] Bend and stretch test [15,22] Shearing stress test [22-24] Direct pull-off method [15,25-39] Moment or topple test [40-43] Electromagnetic tensile test [44] Laser spalation test [45] Ultracentrifuge test [13,22,46-50] Ultrasonic test [13,76] Peeling test (13, 51-54] Tangential-shear test [55,56] Scratch test [50,52, 57-73]... 

Chou, P. and M. Lamers (2005). Quantitative study of magnetic tape abrasivity using accelerated wear testing. Microsyst technol 11,901-906. 

Somewhat similar is the abrasive tape test for plastics (9). This test rubs plaques of plastic against a contact roll covered with bonded abrasive tape. Mass loss in a prescribed amount of contact with the abrasive tape is the metric. The reference material for the test is wrought zinc. This test simulates severe abrasion. This testing standard contains a second procedure that rubs flat plastic specimens against flat plates covered wifti aluminum oxide particles. This is a three-body abrasion tribosystem as opposed to the two-body system used in the tape test These two tests and the Taber Abrasor test compete with each other and none is considered to be a reference abrasion test for plastics. 

This test was developed to rate the abrasivity of head cleaning tapes for magnetic recording devices. Some tapes were more abrasive than others all intentionally contained abrasive particles, usually aluminum oxide, to remove brown stain from heads. The stains were really adhesive transfer of polymer from the tapes that contact tlm heads. The riders in the original test were made from high nickel alloys or other materials that were used for recording heads. This was done to simulate the actual tribo stem. Since that time, it has been learned that type 316 stainless steel balls, that are readily commercially available, produced the same rankings as the more exotic materials. For this reason, 316 stainless steel has become somewhat of a standard for evaluation of the abrasivity of all sorts of web materials. 

---