Influence of washing liquid temperature. You know, that the cleaning effect of the washing liquid increases with the temperature. The temperature of the bath must be adjusted to the type of fibres, state of preservation, their resistance to washing, possibly also to the type of dyes. It is safest to use water at room temperature. If the fibers and fabric allow, the water temperature can be raised to 30-35°C, but only exceptionally even higher, the higher the temperature of the liquid, the greater the risk of fiber and fabric shrinkage.
Influence of the pH value on the action of the washing liquid. The pH value of the washing liquid plays a significant role in washing fabrics, characterizing its degree of acidity or alkalinity. The destruction of fibers and the fading of dyes depends on the pH, therefore it must be adapted to the type of fibers and dyes. Significant deviation of the pH value from 7 (above and below) requires additives that change the pH. For example, with an acid reaction of the solution (tj. below 7) sodium bicarbonate solution is added until the neutral point is reached. However, with an alkaline reaction (e.g.. pH 9 and higher) dilute hydrochloric or acetic acid is added. It is worth recalling here, that 1 -proc. sodium hydroxide solution is characterized by a pH factor 13,5, the same sodium tetraborate solution has a pH 9,2, in case of 1 – proc. formic acid solution pH is 2,2, and hydrochloric acid pH equals 0,7. The best cleaning effect is shown by alkaline washing liquids with a pH higher than 10. Mimo that, wash fabrics in solutions that are as neutral as possible or only slightly alkaline.
