Pinholes in SMS and meltblown come from shot, thin spots, drips burning through or contamination, while pinholes in film come from gels and overstretching. Even a few per square meter can fail a barrier spec. They are found with light tables, inline cameras and hydrohead testing.
Pinholes are showing on the light table every couple of meters, so the MB layer is running too thin.
Also heard as
- pin hole
- hole
Related terms
Hydrohead
Shop and spec clip for hydrostatic head: the water pressure a fabric holds before water comes through.
Shot
Small beads or lumps of polymer that failed to form fibers and sit embedded in a meltblown web.
Meltblown
Web of very fine fibers made by blasting molten polymer from a row of tiny die holes with hot, high-speed air.
Backsheet
Outer, liquid-proof layer of a diaper or pad, usually breathable film laminated to a soft nonwoven.