In 2013 BASF and Bostik secured a series of highly-detailed new patents relating to diaper construction – and specifically to designing products that more efficiently contain and distribute superabsorbent polymers (SAPs).
In world patents WO/2013/060732, 060733 and 060734 and 060735 it is explained that a disposable diaper conventionally comprises a backsheet which is impervious to liquids, typically polyethylene, a topsheet which is perveous to liquids and in contact with the body part, and an absorbent core sandwiched in between.