Carmen Algra, of Tikipunga Primary School, asks :-
What is washing powder made out of?
Simon Ellingham, an industrial chemist with Unilever, responded.
A washing powder is made up of a number of different components that all help water to do the washing.
As strange as it may seem, water is not very good at making things wet. We need a surfactant. They are made up of a "water loving" end - attracted to water - and an "oil/grease loving" end - attracted to fatty, oily stains on fabrics. In the wash cycle, the oil/grease loving end attaches itself to the stain and then in the rinse cycle, the attraction of the water loving end to water helps remove the fatty, oily stain from the fabric.
In water there are ions, for example common salt, which stop the surfactant from doing its job. Builders such as phosphates and zeolites are therefore required to trap these ions, a term known as water softening, and by doing so allow the surfactant to work uninhibited.
Special stain removers break down large complex food materials into simpler things which the surfactant can handle. There are 3 main types of enzymes and all have different jobs. The first one breaks down protein stains such as blood and grass; the second works on fatty, oily stains and the final one, on starchy stains such as chocolate and pasta.
Fillers (sulphates) have two functions - they help soften water and are important in making the washing powder flow freely from the packet.
Silicates and/or carbonates are added to make the high alkalinity required to assist the builder in trapping the unwanted salts so that the surfactant can work properly.
Fluorescers convert unseen UV light into reflected visible blue light which not only makes fabrics appear whiter, but also much brighter.