Some important developments in the 1920s and 30s

These lacquers ('Duco') (trademark) were introduced to the Australian motor industry by BALM Paints in 1928. New factory buildings were erected and qualified staff were taken on to supervise safety, formulation and manufacture. Initially the nitrocellulose was imported, but ICI commenced local manufacture in 1938.

Alkyds were the first family of systems derived from the chemists' new skill in creating synthetic, high molecular weight compounds (polymers) from identical (monomers) or complementary (co-monomers) building blocks. E. H. Carothers (du Pont, USA) had shown in the 1930s that acids and amines or alcohols which had reactive groups at either end of each molecule could be linked to form long chains, polyamides or polyesters. This opened up a wide field of combinations and permutations. The ability to modify the molecular structure of the components, not only the proportions of naturally occurring substances as in the past, gave paint chemists new dimensions of creativity. They could now tailor molecules to desired properties such as drying time, colour and durability. Alkyds were such a polyester system based on the reaction of two main polyfunctional compounds, an alcohol (glycerol) and an acid (actually, phthalic anhydride), modified by a drying oil such as linseed oil. Alkyds rapidly displaced the old oil based systems. The first recorded manufacture of alkyds was by BALM in 1937. The technique used was crude by today's standard but in due course all larger paint companies made their own alkyds.

Alkyd resins for enamels were developed in the US and Europe for spray topcoats in the automotive industry and soon Ford, Australia used these finishes, supplied locally, in their assembly plant. Paint manufacturers in Australia, however, saw additional opportunities in modifying both the oils and the proportion of oil in the alkyd to formulate 'easy-to-brush' enamels that would appeal to the local 'do-it-yourself' painter. Previously, paint with decorative appeal had not been easy to apply, and painting was the domain of the tradesman.

Oils were at first imported into Australia, but progressively a local crushing industry was established by companies such as Harold Meggitt. Linseed oil, with a high degree of unsaturation, was the preferred oil for air drying finishes, but less reactive oils, such as soya and even the highly saturated coconut, were progressively introduced. Thus paint chemists became familiar with polymer design and the effect of oil type on final properties.

Urea formaldehyde resins, developed in the late 1930s, paralleled the introduction of 'short oil' stoving alkyds. Formed by the etherification reaction between urea and formaldehyde in the presence of (typically) butanol, these resins required sealed reactors. They crosslink with alkyds on heating to form hard films with better chemical and UV resistance than air dried alkyds.

With the increasing sophistication of polymer chemistry in paint systems the need for graduate chemists grew. It was the beginning of scientific control and the transition to independent local research.

As in other areas, the war shortages retarded growth, but at the same time the need for emergency substitutes stimulated imagination. One such need was camouflage paint with an unusual specification: Earth colour, low gloss, and rugged enough to be applied in the field with a broom; it also had to be washable with water. This was the beginning of emulsion paints using water as the continuous phase (Taubman's, late war years) and of the recognition that the incorporation of pigment was more a matter of dispersion than grinding since many pigments were already fine enough in their dry state.

Australian Academy of Technological Sciences and Engineering