Driers

Desiccants, accelerators and hardeners are used in addition to main substances for production of varnish and painting products. Desiccants are combination of metals with organic acids. Carboxylic acids, i.e. naphthenic, aromatic tall oil fatty acids and octanoic acids are used for production of desiccants. KARVAN-L company uses ecologically clean natural petroleum distilled naphthenic acids (DNA), threshold limit value (TLV) of which is 40 times more than of actinic acids. KARVAN-L company produces the following desiccants-naphthenes: Dimethylation Naphthenate Mn Pb is prepared on the basis of special formula allowing to keep stable colour of desiccants. The following actual expendable norms passed the industrial testing on PF-060 and PF-053 varnish based enamels PF-127, PF-268, PF-115. The percentage ratio of chemical is as follows: Co 0.0125, Ca 0.0160, Zr 0.075, Zr 0.031, Pb 0.015, Mn 0.04. Metals with several common oxidation states as cobalt, calcium, zinc, zircon, manganese, lead are used in desiccant production. Each of these metals has different catalytic activity and has its own application, in particular: cobalt desiccant is most effective and can give good results, but usually it is used together with Mn, Ca, Pb. Calcium accelerates drying at low temperature, also eliminates turbidity and irregularity of film. Zinc decreases initial speed of surface drying, but accelerates overall drying. Zinc results in greater hardness of final film. Zircon is used in desiccants of titrimetric effect as replacement of lead and is less toxic, used in combination with Co, Mn, Zn. Manganese is a main desiccant after lead and cobalt and is the most important. It dries not only surface, but also depth of film. It is used together with Pb and Co, thus increasing hardness and transparency of the film. It is not used separately, because the film might become rough and friable.