7
參見UL444:有規(guī)定發(fā)泡實驗:
6.3.2.4 Specimens of PVDF rated 125°C, foamed, or multi-layered insulations 305 mm (13 in) long shall
be placed in a circulating-air oven conforming to ASTM Standards D 5423 (Type II ovens) and D 5374
and aged for the appropriate time and temperature shown in Table 9 for the insulation adjacent to the
conductor. When the insulation is foamed, the aging shall be as specified for the solid insulation. A
minimum of six specimens shall be tested. Insulations with band-marking inks may have the ink removed
before specimens are aged. After removal from the oven, the specimens shall rest for 16 – 96 h in still air
at room temperature and then be wound tightly, for six close turns, around a mandrel having a diameter
no greater than that of the insulated conductor under test. The insulation shall be examined for cracks
using a lens having magnification of 5X. The insulated conductor shall then be straightened, one side of
the tube of insulation sliced off with a knife or razor-blade, and the conductor removed for examination of
the inner surface of the insulation. There shall be no cracks on either the inside or the outside surface of
the insulation.
