Japan’s Unicharm was the first company to introduce superabsorbent polymers (SAPs) to diapers in the early 1980s, quickly followed by the other global leaders in the field.
This set the hygienic disposables industry on a course of gradually reducing the weight of its products, since a gram of SAP could replace four or more grams of fluff pulp. Initially, however, there was quite a trade-off between the desired capacity and the absorbency-under-load of such products. As a result, the first of these new absorbent cores contained just five grams of SAP to 40g of fluff pulp.