Candidate Support Pack - Scottish Qualifications Authority

Soap
Soap is still added to some fully built detergents to add a slightly soft feel to fabrics and
provide lubrication inside the CTW as well as to act as a suds suppressant because
many synthetic soapless detergents will create a very high lather and thus reduce
mechanical action. This lather does not contribute to the cleaning process and can be
difficult to rinse away.
Enzymes
Enzymes are very complex organic molecules which can be added to a wash to digest
specific types of protein, cellulose and fatty soiling. A wash containing enzymes should
be maintained below 50 ºC for at least 10 minutes to enable the enzymes to break down
their particular soiling target.
Bleaching agents
These are sometimes added to built powdered detergent products in the form of sodium
perborate. Sodium perborate is only active between 60 ºC and 80 ºC, although activators
can be added to allow it to become active at lower temperatures. Bleaches built into
detergent products do not have the flexibility of bleaching carried out with separate
chemicals.
Organic chlorine bleaches (DCCA and TCCA) can be added into fully built detergent
formulations, but these should only be used at wash temperatures below 60 ºC to avoid
excessive fabric damage.
In the CTW, liquid bleaches are normally used as these can be more readily dosed by
pumps into the wash process in the right compartment. The most common bleaches
used are sodium hypochlorite (which would normally be used during the rinse stages) or
hydrogen peroxide and peracetic acid (which are only activated at higher wash
temperatures, so are normally used during the main wash stages).
GC8N 22 — Laundry Operations Level 2 5.57