Polyethylene terephthalate film for electrical insulation

摘要

A polyethylene terephthalate film suited for motor insulation is described having the following: (a) an intrinsic viscosity of 0.80; (b) a lateral crystalline size of not greater than 65 Angstroms; (c) an extractable oligomer content of no more than 0.6% by wt.; (d) a hydrolytic lifetime of at least 500 hours; (e) a density within the range from 1.385 to 1.395; (f) no more than 3% by weight comonomer; (g) no more then 1.5% by weight of diethylene glycol as a comonomer; (h) a carboxyl content of no more than 25 milliequivalents per gram of polymer; (i) a particulate content of 0.1 to 2 weight % with the proviso that the polyethylene terephthalate film does not contain an end capping agent; and (j) an embrittlement time at 160 DEG C. of more than 100 days.