How is it possible to design a wipe that 1) does not disintegrate when wet inside its box and 2) disintegrates when wet in a sewage system? Even Andrex's maxim

How is it possible to design a wipe that 1) does not disintegrate when wet inside its box and 2) disintegrates when wet in a sewage system? Even Andrex's maximally biodegradable 'flushable washlets' offering contains 2% plastic fibers.