History

Mechanism Of Action

Primary Driers

Auxiliary Driers

Instantly Applicble

HISTORY OF DRIERS

Driers are a group of metallic soaps containing either alkaline earth metals or heavy metals combined with monobasic carboxylic acids represented by general formula (RCOO)x M, where M is an alphatic or alicylic radical and M is a metal with value x. They are soluble in organic solvents and binders. Driers help drying of Paints after application. Erly attempts in development of driers were made the basis ofn various constants used in oil analysis particularly according to the degree of unsaturation as measured by the iodine value. Accordingly, oils were classified as 'drying', 'semidrying' and 'non-drying'. All fatty oils of vegitable origin contains a proportion of sturated acids like palmetic, stearic and some oleic acids but these make no contrebution to the drying process. Linoleic Acid (9:10, 12:13, Octadecadienoic acid), as its chemical name implies has 18 carbon atoms and two isolated double linkings. In fatty oils of vegitable origin, it is invariable associated with oliec (9:10 Octadeceonic) and saturated acids, and absence of more unsaturated components, a high proportion(more than 50%) is necessory for the oil to appreciable drying properties.

Perinaric acid (9:10, 11:12, 13:14, 15:16 Octadecatetraenoic acid) is remarkable in being the only acid of vegitible origin to have four double linkings. (Conjugated Isomer of Linoleic Acid).

Preparation of Drying oil from raw linseed that would drying less than 24 hours instead of 3-4 days was achived by heating it for prolonged period at fairly high temperature with small quantities of 'driers', most effective of which were compounds of Lead and Manganese. Introduction of Zink white as a pigment for paints led to demand for pale boiled oils with development of Oil soluble driers arround 1485, lead & manganese soap of linseed fatty acids of rosin, 'Linolates' & ' Rosinates' were early compounds to be used this way. Subsequently scientific studies led to improvement being introduction of COBALT in about 1910 and othere soluble driers based on napthenic acid - first produced in Germany in 1925 under trade name of 'Soligen'. For selection of organic acid for conferring solubility of heavy metal salts. Certain mono basic acids, having unsaturation, branched chains and cyclic configuration are most important. For example, naphthenic acid having these charecteristics has low Iodine value and confer good stability towards oxydation. Further octic acid (the branched isomer of normal octoic acid is 2-ethyl hexoic acid) was commercially introduced for making driers in during 1960 as it offers good solubility in oils and thinners and also appreciable water solubility.