Washing Polycarbonate Bottles

I am sure that you are all aware of the factors involved in providing a clean bottle.  These are chemical type, concentration, temperature, physical agitation and time.  However, there is another factor of importance and that is compatibility of bottles with your washing process.

Apart from excessively high temperatures, the factor most likely to affect bottle compatibility is the type of chemical used.  The formulation must be balanced to give good cleaning and appearance with no streaking and maximum bottle life.  Unless the chemical has been specifically formulated for polycarbonate washing, it is likely that problems will arise eventually.

High alkalinity can be the worst offender, but careful formulating will offset the effects of causticity and produce an excellent clean without causing bottle damage.  One of the key ingredients in doing this is the detergent.  By "detergent" I mean a real detergent, not just a mixture of alkali and water softener which is characteristic of many products on the market.  By careful selection of detergent, the bottle will receive protection from the effects of the alkali and, as a bonus, will aid draining and reduce carry over.  If your product does not generate a measured level of foam, it does not contain a detergent.

If your supplier has formulated correctly, he will have carried out compatibility checks on polycarbonate.  The testing involves putting polycarbonate strips under stress by bending and then immersing them in neat product.  The kind of results we obtain are shown in the photo.  This product was highly alkaline with no protection.

You may say that bottle lifetime is not a real concern.  However, there is another, more insidious, factor and that is the formation of microcracks.  These may not be so obvious, but they are breeding ground for bacteria, algae and other undesirables and these bacteria will only emerge after the bottle has been filled for some time, unfortunately when the bottle is with the customer.  Bottle compatibility is therefore important in providing the highest quality product.