A flexible porous web having a permanent humidity sensor for indicating release of material therefrom

摘要: A porous web (5) having a permanent humidity detecting sensor is disclosed in which metal salt (10) permanently bonded the matrix. The undergoes color change from its hydrated to dehydrated state detect of surrounding environment. Nonwoven fibrous webs are especially adapted for containing materials such as fabric softeners that may be released upon conditions conventional clothes dryer treatment and visual detection release softener by sensor.