A Busy Element, That Boron
June 1999

Times were, when shopping for a product to do the household laundry, a packet of soap powder of some brand or another would be just the thing. The product would require just a simple chemical, perhaps with the addition of a perfume or stain remover like straightforward borax.

Now? The detergents we use are extraordinarily complex mixtures of ingredients, matched precisely by expert manufacturers to suit local conditions and usage. Around the world, wash temperatures vary by scores of degrees and the amount of washing powder put into the machine differs. Maybe a stain remover is added separately. And the domestic machine might be loaded at the top or from the front. This affects the amount of water used and hence the amount of detergent needed. All these factors have an impact on what the detergent manufacturer puts into that seemingly simple white powder in the box on the supermarket shelf. And for decades, borates have been a common factor in detergent formulations.

Just consider what we expect a detergent to do. It needs to get dirt out of and off clothes, bleach stains but leave colors alone, maintain fabric softness and deal with germs.

And what, anyway, does 'detergent' mean? In the home, a 'detergent' is something with which you wash clothes or dishes. Scientifically, it is much more precise than that: it has to act at the interface between what needs to be cleaned and the soils that need to be removed, separate them and allow the dirt to be rinsed away. In scientific language, this is a surface-active agent or surfactant.

They work also to alter the surface tension of water (increasing 'wetting'); they dissolve, loosen or bleach stains so they can't be seen; they soften the wash water so other cleaning actions work better; they sanitize the wash and protect what is being washed from damage. Quite a tall order for a simple white powder.

As scientists' insights into the chemistry of the wash have increased, so has the efficacy of the household detergent. On the other side, away from the language of marketing ('washes whiter', 'new, improved'), the householder has mostly been in ignorance of these advances or at least why and how they have been responsible for better products. Those 'white powders' work better and better, and improvements over the years have become expected. Many advances have come from discoveries by scientists that the borates in washing powders and liquids contribute in a great many areas.

It's probable that the value, or even existence of borates in their washes isn't realized by the average supermarket shoppers in Europe. But it is in a way, without them realizing it - most are familiar with Persil* brand, and the name is the clue. With a little grounding in chemistry, you see that the brand name derives from Perborate-silicate.

Before 1907 when Persil was launched, clothes were laundered in soap with 20 Mule TeamŽ Borax often being added separately as a powerful but gentle bleach and fabric conditioner. Persil put a better 'soap' and a bleach into the same package.

Not only did this have the advantage of convenience, but chemists began to discover that the borate (now sodium perborate, produced by reacting borax with sodium hydroxide and hydrogen peroxide, and also other borates) worked to make the detergent better in many different ways as well.

Put there originally as an in-wash bleach (for common and difficult stains in whites and colored fabrics), it is technically a vehicle for the release of available oxygen or 'Avox' which renders many stains colorless. Compared to other Avox-producing ingredients, perborate is highly stable and retains its potency over a very long period, important for supermarket and utility-room shelf life.

Later on it was also discovered that it helps lift some kinds of stains off fabrics by giving the stains the same electrical charge as the fabric (as like repels like, the stain lifts off).

Borates work as detergent 'builders' as well. They improve the performance of the basic detergent chemical, principally by softening hard water, and helping the surfactant to work better. In hard water, prone to forming lime scum, detergents work less well because of calcium carbonate precipitation, which borates repress. Oily dirt also turns into soapy cleaning substances when borates are present - a process known as saponification - a plus to the overall laundering process.

Further advantages of having borates in the wash are that they can stabilize other ingredients, such as enzymes (stopping them from degrading and so significantly lengthening storage shelf life in the supermarket and at home, with little loss of cleaning efficiency). They make sure that the alkalinity of the wash water is best for the wash under virtually all circumstances. They help other components stay dissolved in concentrated liquid formulations, as well as aiding fabric care and effective sanitization.

Borates have been 'in the wash' since the 19th century, when borax even inspired music-hall songs of the joys of wash day and the banishment of dirt. Now as perborates, they are almost universally to be found in European laundry detergents. In the U.S., with the advent of front-loading washing machines, special perborate formulations for the American market are increasing.

And borates are even now moving with the times. With the trend toward lower wash temperatures for energy-saving reasons, borates can be as effective as they were in the day of the hot wash by the addition of so-called activators. New discoveries indicate that even lower temperature perborate stain removal will become a reality.

* Persil is a registered trademark.

A new technical booklet describing the cleaning properties of borates and perborates is available upon request by contacting your local Borax representative or sales office.