"Being an inventor, I invented my way out of it." The chemist
Robert H. Black is the inventor of
Clean Shower, a spray-on product
for rinsing the
shower after each use. Black was motivated by his
wife, who made him clean the shower. The inventor realized that this is
a particularly nasty task, and that any invention to ease this task
would have tremendous
market potential.
Since Clean Shower came onto the market in 1995, sales have indeed
soared. Annual U.S. retail sales for Clean Shower and competing brands
such as Shower Shine, Mist Away and Fresh Shower were already up
to $70 million in 1998.
Judging by sales figures, these products appears to do what they were
designed for. This raises the question how exactly these shower
cleaners work. The key to understanding this is knowledge of the types
of residues are formed in the shower, and the way they are deposited.
Organic residues consist of oils and debris from the
body, usually coated with soap or shampoo. There are also
inorganic deposits like calcium, magnesium and iron from the water. If left to dry, these deposits build up over time. The
damp environment is also a breeding ground for a third type of residue,
namely mold and mildew.
According to the patent, one important ingredient of Clean Shower
is Antarox BL-225 surfactant (a mixed ethylene glycol ether
nonionic surfactant). This compound lowers the surface tension of
the water droplets on the shower walls, causing them to coalesce. This
is called sheeting action: the water glides down the surface in
a thin film.
A second important ingredient is Hamp-ene diammonium EDTA, a
chelating agent. This compound sequesters the ions of the inorganic
salts, rendering them soluble. Most of the inorganic salts are washed
away by the sheeting action. Some of the inorganic salts remain behind,
but the chelating agent and surfactant act as a barrier against residue
buildup; next time the shower is used, the remaining salts are washed
down with the chelating agent and the surfactant.
The sheeting action alone is not sufficient to avoid the growth of
mold and mildew and therefore, Clean Shower also contains a
disinfectant. Other ingredients are isopropyl alcohol, which helps to
dissolve all the ingredients in water and to remove oily human debris,
fragrance, and water.
Brands other than Clean Shower use different compounds to achieve
similar results and not infringe on patents.
Factual sources:
Chemical & Engineering News - December 3, 2001
US Patent 5,910,474: Method of rinsing showers clean