Creep and shrinkage behavior of improved alternate substrates for magnetic tapes

The long-term creep deformation and shrinkage characteristics of improved alternate substrates for magnetic tapes are presented. The substrates include two polyesters (PET and PEN) and aromatic polyamide (ARAMID). PET film is currently the standard substrate used for magnetic tapes and thinner tensilized-type PET, PEN and ARAMID have recently been used as alternate substrates with improved material properties. The thickness of the alternate film ranges from 6.2 /spl mu/m to 4.8 /spl mu/m. The amount of creep deformation is considerably smaller for ARAMID and tensilized-type PET than for PEN. Shrinkage of ARAMID is lower than that of PET and PEN. Based on creep and shrinkage behavior, ARAMID and tensilized-type FET seem to have satisfactory dimensional stability.