Modern disposable diapers are generally made of a cloth-like waterproof exterior, a moisture-wicking inside layer, and an absorbent inner core (in modern diapers usually a dried hydrogel). The first mention of the disposable diaper was made by PauliStr«ím in Sweden, in 1942. The early disposable diapers had an inner of many layers of tissue paper, and were able to hold 100cc of urine, which is approximately one wetting. In the 1960's, a pulp mill was used for the absorbent core, and the disposable diaper became much more popular for the families who could afford them.
Disposable diapers have overtaken the cloth diaper market and put many diaper services out of business due to their convenience and relatively small bulk on the baby. Approximately 18 billion units of disposable diapers were sold in the US in 2004.
Disposable diapers take a great deal of processing and their materials remain intact in landfills for many years -- some reports estimate 500 years. Because disposable diapers wick moisture away from the child's body, children tend not to realize they are wet, which may be the reason that disposable diaper-wearing children toilet train after the age of three. As a result, these children may require 8,000 disposable diapers before they are toilet trained. The result is that, while a cloth diaper costs more per unit, a disposable diaper will cost considerably more over time, as a cloth diaper can be laundered and re-used, whereas a disposable cannot.
Disposable diapers are laced with chemicals obtained unintentionally in production, as well as intentionally in order to improve absorbancy and pull wetness away from the skin. While this system works well in keeping skin dry, it also provides a potential skin irritant. Cloth diapers are most commonly made of industrial cotton, which is grown in conjunction with the heavy use of pesticides. The fabric is also usually bleached white. Alternative materials which are grown without pesticides, such as unbleached hemp and organic cotton exist.